Inviting the stranger in: Intimacy, digital technology and new geographies of encounter

Digital technologies are profoundly reshaping how people relate to unknown others, yet urban studies and geographies of encounter have yet to adequately incorporate these changes into theory and research. Building on a longstanding concern with stranger encounters in social and urban theory, this paper explores how digital technology brings new possibilities and challenges to urban life. With examples ranging from GPS-enabled apps for sex and dating to sharing economy platforms that facilitate the peer-to-peer exchange of services, new practices mediated by digital technology are making many stranger encounters a matter of choice rather than chance, and they are often private as much as they are public. This paper examines these changes to develop a conceptualisation of stranger intimacy as a potentially generative form of encounter involving conditional relations of openness among the unacquainted, through which affective structures of knowing, providing, befriending or even loving are built. We offer an agenda for researching stranger intimacies to better understand their role in generating new kinds of social and economic opportunity, overcoming constraints of space and place, as well as generating dynamics of inclusion and exclusion, privilege and disadvantage. The paper concludes by considering what critical attention to these encounters can offer geographical scholarship and how an emphasis on digital mediation can push research in productive directions.


I Introduction
To inhabit the city is to live in a world of strangers. Encounters with unknown others are widely regarded as a defining feature of the urban experience (cf. Amin, 2012;Lofland, 1974;Sennett, 1974;Simmel, 1950Simmel, [1908). Affirmative accounts of the desires, opportunities and potentials emanating within cities often centre on interaction among strangers (cf. Carr et al., 1993;Sennett, 2006;Stevens, 2007;Turner, 2003;Wood and Landry, 2007) and they underpin normative visions of urban life as the cosmopolitan gathering of difference (cf. Jacobs, 1961;Sandercock, 1998;Young, 1990). The figure of 'the stranger' also features in discourses of social anxiety, fear and danger (cf. Ahmed, 2000;Koefoed and Simonsen, 2011), giving impulse to new forms of urban surveillance, segregation and control (Allen, 2006;Low and Smith, 2006;Minton, 2012). The balance between positive and negative feelings towards strangers in public culture, Ash Amin (2012: 2) argues, results from the synthesis of habits of interaction, 'through intricate and often interwoven sets of biopolitical, behavioural and affective forces that are simultaneously ingrained and unstable'. Indeed, to live in the city is to participate in a routine calculus of exchange with unknown others: ongoing negotiations of proximity and boundaries premised on varying degrees of familiarity, intimacy and trust. This paper examines how stranger relations are being reconfigured by new social practices mediated through digital technologies. With examples ranging from location-based apps that connect people with similar interests, to online platforms that facilitate the peer-to-peer exchange of services, emerging public cultures of encounter are bringing new possibilities to urban life. Digital technologies are multiplying and extending the times and spaces where people engage in dialogue and exchange. They are helping people overcome constraints such as local cultural norms governing intimacy, as well as logistical barriers to meeting face-to-face or in public. They are also extending access and experiences of intimacy to wider demographics, as digitally mediated encounters move from the niche into the mainstream (Hobbs et al., 2017;Maalsen, 2020). The COVID-19 pandemic has accelerated and extended these trends in unprecedented ways. In contrast to the focus on spontaneous encounters that underpin much theorisation on public life, meetings between strangers are now frequently planned in advance and take place in relative privacy, increasingly within spaces of the home. They are facilitated via sophisticated digital methods and algorithms for scoping, selecting and verifying potential contacts (Bialski, 2011;Germann Molz, 2014;Race, 2015). As contact among strangers becomes a matter of choice as much as chance, many long-standing norms and conventions through which intimacy and trust among strangers is negotiated are being reconfigured. These forms of encounter, however, will not be readily available to everyone, everywhere. For not only do technological developments bring forth novel kinds of pleasure and possibility, they also entail new forms of social distancing and exclusion.
Against this background, the paper has three aims. First, it seeks to place developments in digital technology more firmly into urban studies and geographies of encounter. Our argument here is not that urban inhabitants are necessarily becoming more or less comfortable in the presence of strangers. Rather, it is that researchers concerned with questions of encounter and social (dis)connection too often ignore the centrality of digital technology in much of contemporary public life. Second, the paper conceptualises stranger intimacy as a potentially generative form of encounter that technology facilitates. Intimacy here is not understood as simply romance or sex, but a wider epistemology for thinking about connection (Berlant, 1998;Shah, 2011). Stranger intimacy is thus defined broadly as conditional relations of openness among the unacquainted, however fleeting, through which affective structures of knowing, providing, befriending or even loving are built. Our approach marks a distinction from the focus on how strangers are often constructed as 'Others' in discourses of urban or national belonging (cf. Ahmed, 2000;Amin, 2012;Koefoed and Simonsen, 2011). Instead, we draw attention to the digitally mediated practices through which encounters are valued and pursued. Third, this paper sets an agenda for researching stranger intimacies in order to better understand their role in generating new kinds of social and economic opportunity, overcoming constraints of space and place, as well as generating dynamics of inclusion and exclusion, privilege and disadvantage. Through these aims, the paper challenges and extends scholarship concerned with geographies of encounter (Valentine, 2008;Valentine andSadgrove, 2012, 2014;Wilson, 2017), practices of hospitality and intimacy (Bell, 2007;Miles, 2018;Germann Molz, 2014), public-private relations (Barnett, 2014;Qian, 2018) and home-city geographies (Blunt and Sheringham, 2019;Maalsen, 2020). A key contribution offered here is a demonstration of the profound impacts that digital technologies are having on how people often meet, raising new questions about emerging geographies of home, public and private, the domestic and the urban, and the changing ways that people live and relate to one another in contemporary society.
The paper proceeds as follows. Section II critically examines how encounters with unknown others have been problematised through the figure of 'the stranger' in social and urban theory. It highlights a tendency in the literature on encounter to neglect the impacts of digital technological change and shows that research tends to narrowly conceive where and how encounters with strangers often take place. Section III outlines how mobile and locationbased digital technologies are reshaping encounters and intimate relations among strangers more broadly. We draw on our own research over the last several years to sketch new contours of stranger relations facilitated by a) location-based media technologies for sex and dating and b) new forms of entrepreneurial activity associated with the sharing economy. In Section IV, we conceptualise stranger intimacy as a way of describing relations of openness among the unacquainted, and for attending to the particular qualities and intensities this form of encounter entails. Identifying key principles for future inquiry, we call for further investigation into the ways in which individuals and groups are differentially enabled to benefit from these developments. The paper concludes by considering what critical attention to stranger intimacies can offer geographical scholarship, particularly in light of the COVID-19 pandemic, and how an emphasis on digital mediation can push research in productive directions.

II Encountering the unknown other
The question of what it means to live in a world of unknown others has been a foundational topic in social and urban theory. Initiated by the classic writings of George Simmel (1950Simmel ( [1908), 'the stranger' is a relational figure who enters into an existing group that defines itself through spatial boundaries. The stranger's arrival may be welcomed or contested, but either way their presence produces 'a specific form of interaction' (1950 [1908]: 402) in which judgements of belonging, inclusion/exclusion and place attachment/detachment must be reckoned with (cf. Koefoed and Simonsen, 2011). Elsewhere, Simmel (2010Simmel ( [1903) incorporates the stranger encounter as an ordinary, fundamental feature of metropolitan life -a key component of the intense bombardment of external stimuli that individuals must register, evaluate and manage as part of the everyday. Routine-ness thus renders stranger relations as largely ambivalent, intensifying only when threats, desires or opportunities are perceived.
The extent to which stranger encounters diminish traditional social ties and community relations was the focus of much early urban sociology (cf. Durkheim, 1933(cf. Durkheim, [1889; Park and Burgess, 1925;Tönnies, 1936Tönnies, [1887). It is a theme returned to throughout much of the 20th century in writings on communities and urban life, where relations of impersonality are understood as generating problems of indifference, alienation and insecurity (cf. Bauman, 2000;Putnam, 2001;Putnam and Feldstein, 2004). Conversely, Richard Sennett (1974) argues that, by the middle of the past century, experience gained in the company of strangers came to be seen as crucial to the formation of individual personalities. Without exposure to strangers, 'one might be too inexperienced, too naive, to survive ' (1974: 24). In a similar vein, Habermas's (1989Habermas's ( [1962) account of the emergent bourgeois public sphere drew attention to the domestic and commercial architectures that established distinctive spaces where private reason could be developed. Habermas and Sennett both offer accounts that support narratives of decline in public life over the late 20th century. On the other hand, they can also be connected to more affirmative theorisations of cities as 'worlds of strangers' (Lofland, 1974). Here, the enchanting possibilities of encounter, the opportunities for social learning and connection, the freedom of anonymity among the crowd, and the potential for solidarity amidst life shared in common provide reasons for celebrating urban life as the cosmopolitan gathering of difference (cf. Jacobs, 1961;Sandercock, 1998;Young, 1990).
The ambivalence of the stranger is most fully articulated in the work of Zygmunt Bauman (1991Bauman ( , 2000 who extends Simmel's epochal characterisation of stranger relations. In modernity, Bauman argues, the figure of the stranger was taken to represent all that was excluded and delegitimated in discourses of order, sameness and totality (Bauman, 1995). Individuals and communities identify strangers in order to define themselves, constructing them as 'Others' as boundaries are drawn and borders are enforced (cf. Ahmed, 2006;Faier and Rofel, 2014;Said, 1978). Postmodernity, in contrast, sees the stranger no longer as a threat to social order, 'but a reminder of difference to be celebrated, protected and lovingly preserved' (Bauman, 2000: 54). And yet, denunciations of multiculturalism and the spread of xenophobic sentiments suggest a hardening against utopian visions (Amin, 2012). Public discourse on issues ranging from crime and social cohesion to immigration and terrorism position the stranger as a figure whose very presence poses a threat to urban public spaces and national borders -constituting what Sara Ahmed (2000) calls 'stranger danger'. Attributing unknown others to this category relies on prior histories of encounter, and on mediated relations that draw other bodies and other spaces into determining that the person being encountered has already come too close. In the words of Koefoed and Simonsen (2011: 346): 'every time we meet the "undecidables" we seek to re-establish ways of recognition, not only by reading the body of this particular "stranger" but also by trying to tell the difference between him/her and other strangers'.
A great deal of geographical research in recent years has focused on the dynamics of stranger encounters to inform academic and policy debates about social cohesion. Notably, Gill Valentine (2008) outlined something of a 'cosmopolitan turn' early in the 21st century as influential geographers such as Amin (2006), Laurier and Philo (2006), Massey (2005) and Thrift (2005) contemporaneously retheorised urban togetherness. Although scantly incorporating developments brought forth by digital technology, this body of work called for greater attention to the potential for pluralistic and hybrid cultures to form through relations of proximity and encounter with strangers in spaces of public life. This has been borne out in research ranging from examinations of everyday life in diverse urban neighbourhoods (Koefoed and Simonsen, 2011;Wessendorf, 2013Wessendorf, , 2014 as well as smaller cities and towns (Leitner, 2012;Swanton, 2010). Such work has inquired into the routine encounters involved in activities such as shopping at markets (Watson, 2006), bus passengering (Wilson, 2011), walking and cycling (Brown, 2012;Middleton, 2018), tourism (Gibson, 2010) and migrant integration and community cohesion projects (Askins and Pain, 2011;Matejskova and Leitner, 2011). It has also extended to more-thanhuman geographies of organisms, objects, materialities and atmospheres that constitute urban experiences, attention to which can help in grasping dynamics of encounter and social interaction (Darling and Wilson, 2016;Gandy, 2012;Latham and McCormack, 2004).
Reflecting on this cosmopolitan turn, Valentine (2008) called for geographers to avoid any romanticisation of the possibilities of encounter and instead consider more critically how different forms of contact may translate into attitudes of respect for difference, but equally may leave intolerant values unmoved or even hardened. A key research theme has thus become examining particular ways in which 'enchantment' and disenchantment emerge through interaction and cohabitation with difference (cf. Darling and Wilson, 2016;McNally, 2019;Teo and Neo, 2017;Watson, 2006;Wessendorf, 2013;Wilson, 2011). Working in this vein, Helen Wilson has offered an open-ended reading of encounter that recognises a mixed bag of possible emotions and attachments: meeting strangers can be 'joyful, fearful, anxious, uncanny, enchanting and hopeful, and how they are named and experienced as such is of critical import ' (2017: 459). She argues that encounter is undertheorised and calls for different kinds of encounters to be considered more fully to understand what they might entail. And yet, like most geographers working on questions of encounter, Wilson follows Valentine in focusing on encounters that are primarily spontaneous and face-to-face, missing a whole range of scenarios through which digital technology brokers human contact (although see Adams, 2017;Cockayne et al., 2017;Miles, 2017;Richardson, 2015).
Given that encounter has been located as 'firmly within the remit of difference, rupture and surprise' (Wilson, 2017: 452), we argue that digital technology should be a fundamental part of any inquiry into how unknown others meet in contemporary society. Indeed, failure to foreground the digital can give a skewed sense of what many forms of social connection entail. For example, Wilson argues that encounters have historically been coded as a meeting of opposites, read through Manichean grammars of 'us vs them' (Rovisco, 2010). But the suggestion that encounters 'are fundamentally about difference' (2010: 452) precludes a consideration of the way digital platforms and social media technologies are often about connecting those with shared affinities and similar interests. Relatedly, while Wilson notes that 'common descriptors of encounter present it as a meeting that is 'casual ', 'undesigned' or 'chance' (p. 462), in geographies of encounter enabled by new digital technologies the very opposite is often true. The platforms proliferating in both sharing economies and sex and dating applications broker meetings that are not exactly spontaneous. They have more likely resulted from searching, screening, selecting and engaging in online dialogue. Rather than being undesigned, face-to-face meetings are deliberately arranged for mutual availability and convenience, and they are not chance encounters (serendipitous though these may be, especially where romance is concerned) but premeditated. Finally, although it has been recognised that the fleeting nature of encounter has been overemphasised to the detriment of attending to more sustained engagements (Valentine and Sadgrove, 2012;Wilson, 2017), the extent to which digital technology facilitates more enduring relationships has not been fully explored.
Importantly, stranger encounters are not only public but often private or domestic too. Valentine andSadgrove (2014: 1981) have questioned the 'primary focus on urban public spaces as sites of encounter' in their call for more attention to the 'significance of both "private" and institutional spaces where individuals' understandings of difference are negotiated and contested'. This call has yet to be fully taken up, although queer scholarship has long highlighted the way in which quasi-public or private spaces such as bathhouses, salons, sex clubs or the domestic space of home have provided important sites for encounter and the formation of counter-public spheres (Berlant and Warner, 1998;Chauncey, 1995;Warner, 2002). Indeed, the home -often (incorrectly) understood to be a sacred, sealed-off interior distinct from public life (cf. Blunt and Dowling, 2006;Kaika, 2004) -is frequently a site where stranger intimacy takes place (Gorman-Murray, 2006;Maalsen, 2020;Race, 2015). A range of feminist scholarship has drawn attention to how the home has served as a meeting point through which women have long connected and mobilised (Hayden, 1984;Shiach, 2005;Wilson, 1992). Conceptually and empirically, home is a well-established focus of geographical research, understood as a physical and imaginary space key for identity formation and belonging, but also a space bound up in relations of power and often a locus of alienation, fear and even violence (Blunt, 2005;Blunt and Dowling, 2006;Brickell, 2012;Gorman-Murray, 2006). However, we argue that contemporary reconfigurations of digital technology re-present home as a generative site for thinking about stranger relations.
Blunt and Sheringham's (2019: 829-830) recent work on 'home-city geographies' calls for a more robust examination of 'the interplay between lived experiences of urban homes and the contested domestication of urban space'. They develop an agenda that emphasises how dwelling and mobilities intersect between domestic and urban scales and unsettle the boundaries between them. We suggest that work in this vein might also attend to the ways in which homes are increasingly sites of encounter and new social relations (cf. Bialski, 2011Bialski, , 2018Koch, 2020). While a number of research engagements have stepped out of domestic spaces to examine sites of home-making (Burrell, 2014;Koch and Latham, 2013;Kumar and Mukarova, 2008), here we are interested in inverting this orientation to focus on the process of inviting unknown others in. Blunt and Sheringham's discussion provides a helpful way of understanding the enfolding of home with wider urban social and material contexts, although it does not consider the role that digital technology often plays in these processes. Apps and digital networking platforms have become key to how many people find a home. As housing costs increase and ownership rates decline, this increasingly means sharing one's home with previously unknown others. Maalsen (2020) has demonstrated that shared housing is now practised longer and by wider demographics than previous generations, and that digital platforms are key to access and experiences of home sharing. Platforms are also now central to how many people meet and communicate with neighbours and area residents, discover local events and services, and navigate the wider cityscape. Further, in contexts of mobility such as tourism and business travel, platform technologies that connect people to fellow travellers, local residents and private homes are increasingly common strategies for developing meaningful relations as part of their travels (Bialski, 2011(Bialski, , 2012Germann Molz, 2014).
We now turn to examine different forms of 'inviting the stranger in' facilitated by digital technology. Our aim is to draw attention to day-to-day practices through which social connections and economic opportunities are pursued through meeting people outside of one's existing networks. Strangers are conceived throughout as simply unknown others, rather than as discursively constructed figures of exclusion. For as Koefoed and Simonsen (2011: 346) argue, 'the stranger takes up different roles depending on the context in which the relation is performed'. Instead of pivoting between optimistic and pessimistic interpretations of the figure of the stranger and the times we are living in, we want to promote more sustained inquiries into how, why and to what effect people go about engaging with unknown others in an effort to develop new forms of connection, intimacy and income.

III New technologies of stranger encounter
This section focuses on two domains in which stranger encounters are brokered through digital technology, drawing on our own research in the US and UK. First, we consider GPS-enabled location-based apps through which people meet one another for sex or dating. Second, we look at peer-to-peer networks associated with so-called 'sharing economies' through which people connect to exchange goods, services, experiences or accommodation. These two examples represent distinct domains of social life yet share commonalities in their use of digital technology that positions strangers as potential customers, collaborators, hosts, guests, friends or romantic partners. They also show how the times and spaces of encounter and engagement are multiplied and extended via apps and digital platforms. We use these examples to set up a conceptual framework for stranger intimacy in Section IV to better understand and critically analyse how digital technologies are reshaping social encounters and connections.

Sex and dating apps
Intimate encounters with strangers have been technologically mediated for a long time. From 'lonely hearts' adverts in newspapers to online chatrooms, technologies have expedited love and/or sexual encounters with progressively greater specificity and in shorter time frames (Campbell, 2004;Cocks, 2002;Grov et al., 2013;Miles, 2018). Virtual worlds were initially conceptualised as distinct from 'real' spaces, but as technology has progressed, digital-physical hybridisation has led to more sustained relationships between the two entities (Rheingold, 2002;Kitchin and Dodge, 2011;Farman, 2012;Miles, 2017). Today, locative media technologies that use GPS to locate other app users in the vicinity have come to play a key role in the social landscape of modern societies. Their use has proliferated with the wider adoption of 3G, 4G and mobile Wi-Fi that facilitate high-bandwidth internet. Location-based apps for sex and dating such as Tinder and Grindr are only a decade old, but count many millions of users globally (Bearne, 2018), including a disproportionately high membership amongst sexual minorities (Anderson, 2018;Duguay, 2019).
Two key features make current partnerseeking technologies distinctive in how they multiply routes to, and the nature of, encounter: their portability and their locational ability. They are built into smartphones or tablets that people can take wherever they go, and they enable the user to search for others within an area also interested in finding someone for friendship, dating or sex. Whether one is inside their home or out in the city, at leisure, work or in transit, they can overlay physical reality with a set of virtual capacities that facilitate seeing, being seen by, and interacting with potential matches. In earlier, less mobile, iterations of digital technology, a person generally had to be in the same physical space to meet someone new, or periodically check in to receive messages via classified ads, telephone hotlines or desktop websites. Today's conditions of 'constant connectivity' (Gordon and de Souza e Silva, 2011) mean that one is almost always online and able to send and receive messages. Further, these products extend possibilities for initiating contact via a 'wave', 'woof', 'nudge' or 'match'. These provide private ways of working around the social anxieties of 'impression management' in public spaces (Goffman, 1959) by offering 'tickets' for conversation among the unacquainted (Sacks et al., 1992) in ways that are casual, quick and often playful. Indeed, the intensity of impression management is potentially reworked digitally as the time of encounter is stretched temporally and can take place shielded from the public embarrassment of rejection or more serious consequences that can come with transgressing social norms and taboos.
Another key aspect of how location-based apps are reshaping encounters is that they enable users to scope, verify and filter potential matches with far greater efficiency than previous formats. Vastly more potential partners can be found online than are present in physical venues such as bars or nightclubs, so the time spent searching for encounters is theoretically condensed. However, the sense of immediacy promulgated by apps means that, paradoxically, users often articulate their experiences as a waste of time (Miles, 2017). In keeping with rather mixed verdicts on the lived experiences of 'mediated' or 'networked intimacy' (Attwood et al., 2017;Chan, 2018;Cockayne et al., 2017;Hobbs et al., 2017), some users feel that apps serve as a barrier to intimacy, because too much information shared in advance negates the serendipity of physical encounter, or because users become habituated to the routine of continuously seeking out new contacts at the cost of developing existing relationships (Miles, 2017(Miles, , 2019Race, 2015). App use also entails various forms of 'digital labour' (Richardson, 2015;Scholz, 2013) including setting up and cultivating one's profile, marketing oneself in a way that invites interest, needing to frequently check into the app, and engaging in online conversations that are unwanted or 'go' nowhere.
Technologically-mediated forms of sex and dating have always diverged from more traditional formats, in that the first meeting is not a face-to-face encounter: it takes place in writing, on the phone, or via images on a screen. When it comes to meeting in person, location-based media technology has helped to popularise the sidestepping of public or quasi-public meeting environments in favour of the domestic space of the home. The phrase 'Netflix and chill' has become a common trope in Anglo-American popular culture in part because of the ubiquity of the in-home first date or sexual encounter, typically pre-arranged through an app (Roose, 2015). This is not true for all people, of coursehousing conditions for many make it difficult or impossible to have a stranger around. Safety is another concern, as letting a stranger in to the home (or entering into the home of a stranger) can come with all kinds of risks. However, meetings outside the home are not always safe either. Arranging first encounters with unknown others in the relative privacy of home is popular because it often requires less effort, is more efficient, more comfortable, and more discreet than meeting out in public (Gorman-Murray, 2006).
Sex and dating apps demonstrate how the very nature of encounter is changing as a result of mobile digital technologies. They multiply possibilities for engaging with unknown others, connecting people physically or virtually who are just metres away but might not otherwise meet, as well as stretching what it means to be proximate, allowing users to search and communicate across a much wider geographical territory. They call into question the nature of encounter as serendipitous, undesigned or chance (cf. Turner, 2003;Watson, 2008;Wilson, 2017), for they are premised on the efficiencies of being able to scope, filter and screen potential partners with remarkable specificity in terms of desired traits. Operating through mobile devices means that encounters can be untethered from fixed spaces or times; for sexual minorities in particular this brings the potential of queering spaces and providing routes to encounter that might otherwise be dangerous or impossible. Many gay and bisexual men have seen these technologies become central not only to how sex and dating are arranged, but as part of wider socialities of friendship, local networking and information gathering (Miles, 2019;Wu and Ward, 2018). However, these technologies have also been hugely influential to mainstream, heterosexual audiences too. Encounter and interaction through apps and digital platforms have become a fundamental part of the contemporary landscape of sex, dating and friendship among strangers in many public cultures around the world.

Sharing economies
Over the past decade, there has been pronounced enthusiasm and investment directed towards new forms of exchange that open up resources and relationships normally considered private to a provisionally public audience. Enabled by digital technologies and online platforms, the term sharing economy is a 'floating signifier' (Nadeem in Schor et al., 2015;Richardson, 2015) for an array of activities premised on peer-to-peer networks, often facilitated by the reconfiguration of established norms and spatial boundaries, and the subversion of formal regulations (Botsman and Rogers, 2010;Slee, 2016;Sundararajan, 2016). Best known through corporate platforms such as Airbnb or TaskRabbit but also practised through a host of smaller scale and non-commercial arrangements (Hall and Ince, 2018), novel kinds of 'stranger sharing' (Schor, 2014) are transforming how millions of people globally organise entertainment, hospitality, accommodation, transportation, and the exchange of goods and services.
Stranger encounters facilitated by sharing economies are not entirely new either: people have long invited others into their homes to perform services such as cleaning, maintenance and repair, gardening and pet care. Platforms such as TaskRabbit essentially provide an updated way of connecting consumers to local listings for individuals and agencies offering services. A key point of distinction is that digitisation facilitates more efficient forms of searching, comparing, communicating, and making payment; 'informational interactions' (Wittel, 2001) that reduce reliance on preexisting communities or local knowledge. More profoundly, digital platforms and apps offer mechanisms for verifying reputation and leaving public feedback, greatly extending possibilities for trust among strangers to be established online prior to meeting in person (Germann Molz, 2014). One's presentation-of-self and 'digital reputation' (Hearn, 2010) can operate as a form of currency, providing premium access to networks and opportunities (Botsman and Rogers, 2010;Germann Molz, 2014). New possibilities for monitoring accountability have made people more comfortable opening up private property to strangers. An early example of this is 'ridesharing' companies like Uber, Lyft, or Didi in China, that have made it common for drivers to use their own automobile as a taxi. Homes are also being opened up in new ways through platforms like Sofar Sounds that turn studios or loft apartments into temporary event spaces in hundreds of cities around the world every night of the week (Janotti and Pieres, 2018), or secret supper clubs and underground restaurants in which homes become makeshift restaurants for a night (Koch, 2020).
Sharing economies are also fostering more intimate encounters at home. Travel accommodation provides a particularly apt example. Couchsurfing.com, counting 15 million members worldwide, connects those travelling with hosts willing to let a stranger sleep on their floor, couch or spare bed. Remarkably, the platform operates on a goodwill rather than financial basis; the platform stipulates that guests are forbidden from making payments, although they are allowed to give small gifts. There is more than just a gift economy at work, however. Successful host/guest exchanges make both parties more attractive to others when seeking out future stays. Ethnographic research has highlighted how users are afforded an array of opportunities for meeting new people, personal growth and shared experiences, saving money and having unique and pleasant travels (Bialski, 2011(Bialski, , 2012Ince and Bryant, 2018;Schuckert et al., 2018). Yet the encounters facilitated are not always altruistic. They can involve interactions marked by tension, awkwardness and burdensome expectations, such as guests feeling compelled to engage in sustained conversation (Bialski, 2012). Perhaps unsurprisingly, commercially-driven forms of peer-to-peer accommodation have become far more common. Ubiquitous in this regard is Airbnb, which connects those renting out a spare room or an entire home to another traveller. Users are verified by the company's platform, and are then able to search their travel destination and filter potential hosts according to dozens of preferences. Hosts in turn are able to vet potential guests. This inevitably leads to filtering based on homophilic affinity and discrimination based on prejudice (Edelman et al., 2017). However, for frequent users, the vetting process becomes routine -compressed such that a handful of positive reviews or the designation 'super host' is enough for trust to be established and a room to be booked. The popularity of the platform's 'instant booking' feature speaks to how common and commercialised this form of inviting the stranger in has become, as does the fact that many employers now provide reimbursement for business travel using the site. Spending a night in a stranger's home has now become an ordinary part of travel for millions of people around the world.
Sharing economy activities further demonstrate that conceptualisations of encounter need to be adapted and refined. Spaces once seen as relatively bounded and off-limits to unknown others are being opened up in multiple domains of social life, further extending Valentine and Sadgrove's (2014) reframing of encounter as something primarily associated with public space. At the same, digitally enabled peer-topeer networks are reconfiguring and, in some cases, sidestepping conventional boundaries between what is public and what is private (Koch, 2020). Sharing economies frequently involve capitalising on domains of life conventionally removed from monetisation.
They are an important source of income and cost-savings for many people, yet as Bialski (2018: 83) puts it, they have also 'placed some of the most intimate and private spheres for purchase: namely, the home and everything that comes with it: privacy, intimacy, candidness, and authenticity'. This raises new questions about the ways that financial motivations often underpin different forms of contact, as well as how market forces redefine sociability and enter into affective domains of life. However, this section has also shown that encounters brokered through sharing economies are often more than solely economic. They are frequently premised on acts of 'lighter touch sociality' (Thrift, 2005) that characterise convivial forms of urban togetherness. They also involve forms of care and mutually beneficial exchange (Ince and Bryant, 2018) that align with aspirations for the 'hospitable city' to be forged through interactions between hosts and guests (Bell, 2007). While arguments about the generative possibilities of stranger sharing could easily be conflated with techno-utopian framings of the sharing economy, emerging critical scholarship has outlined the need for rigorous inquiry into the impacts of these new practices and their differences across space and time (Hall and Ince, 2018;Richardson, 2015).
To conclude this section, the examples of sex and dating apps and sharing economy platforms demonstrate how, for millions of people globally, meeting strangers online for intimate encounters has become normalised. This is because doing so offers experiences and rewards that are convenient, informative, meaningful and which were less readily available in pre-digital times. We believe that as people continue to live highly mobile and interconnected lives, digitally mediated forms of intimacy among strangers will become an increasingly common part of everyday life. This is in part because, as Tuan (1986) suggested, strangers are an infinite source of possibility for connection, inspiration and renewal -for, as he notes, all friends and lovers were once strangers. At the same time, apps and platforms, as well as individual user experiences, are invariably connected to wider social capital processes through which actors attempt to gain social, cultural, economic or other kinds of desired advantage (Ellison et al., 2010). As digitally mediated encounters become mainstream, habits of interaction are being reworked and have the potential to reinforce or unsettle the behavioural, biopolitical and affective forces figuring into how strangers are routinely judged (cf. Ahmed, 2000;Amin, 2012). As geographers and urban scholars pursue these concerns alongside questions about the potential and dynamics of encounter, it is crucial that the changes being brought through digital technology are registered. The paper therefore now turns to consolidate an agenda for further research and analysis.

IV Researching stranger intimacy
How might geographers better engage with the kinds of encounters being mediated through digital technology? Is there a need to rethink the affirmative possibilities and critical concerns associated with urban life as a gathering of strangers? To invite inquiry on questions such as these, this section introduces stranger intimacy as a way of describing encounters marked by openness and trust among the unacquainted. Doing so provides a conceptual frame for attending to the particular qualities and intensities that this form of relation can entail. It also opens up new avenues for geographic research that examines the motivations and possibilities of encounter, as well as ways that digital technology might diminish or restrict spontaneous forms of encounter. We then outline three principles that any inquiry into the relations of digital technology, encounter and intimacy should bear in mind.
Stranger intimacy provides a way of describing how unknown others engage in interpersonal relations of sharing space, knowing, caring, providing and befriending one another. While seemingly an oxymoron, placing 'stranger' and 'intimacy' together signals that strangers are often more-than-Other, while intimacy provides an epistemological frame for attending to the formation of personal attachments and engagements (cf. Berlant, 1998;Shah, 2011). Intimacy need not be understood narrowly as a romantic or sexual connection, although this may be part of it. Rather, it refers to an openness of the self and of personal space as much as it does the body (Jamieson, 1998;Stoler, 2006). Stranger intimacy incorporates the willingness to engage in conversation with unknown others where meaningful stories, experiences and inner feelings are exchanged. It can involve giving access to resources such as a place to sleep, a seat in one's car, space in the kitchen or bathroom, or even keys to the house. Such practices can be motivated by affective forces such as romantic or sexual pursuits, an ethic of care or hospitality, an interest in meeting new people and pursuing new cultural experiences, or simply the wish to make or save money. Indeed, stranger intimacy often involves complex entanglements of social, psychological and economic desires. Understood broadly, attending to stranger intimacy prompts researchers to consider wide ranging forms of social connection, from transient forms of encounter to more lasting associations, through which people forge meaningful relationships outside of friend networks or institutions of family, work, school or community group (Shah, 2011).
Intimate encounters among strangers sometimes happen spontaneously through chance meetings on public transport, in cafes and bars, in queues and in waiting rooms, but coordinated through digital technology they more oftenthan-not result from prior planning. This includes scoping platforms for potential matches, filtering for preferences, and communicating to share information and establish trust.
Judgements made rely on a digitally mediated 'metaphysics of encounter' (Adams, 2017) that encompasses instincts and routinised behaviours, including calculations based how others appear visually and communicate textually, conditioned as these are by biopolitical impulses, prejudices and prior experiences (cf. Adams, 2017;Amin, 2012;Miles, 2017). Contact brokered online sometimes stays in the virtual world (McGlotten, 2013;Miles, 2019), particularly in places where local culture makes meeting in public difficult -such as in parts of the Middle East where men and women cannot easily mix (Costa and Menin, 2016;Kaya, 2009) or for those with limited physical mobility, where online fora may offer a social lifeline (Dobransky and Hargittai, 2006). Digital technology can not only extend possibilities for stranger intimacy beyond the immediately proximate, it can also intensify these encounters by transmitting audio, images or video that make them feel more proximate (Cockayne et al., 2017).
Face-to-face stranger encounters are often marked with a particular intensity, as demonstrated empirically by scholars such as Bialski (2012), Brown (2012), Laurier and Philo (2006), Valentine (2008), Watson (2006) and Wilson (2011). Expectations of intimacy can bring heightened emotions, especially when a planned meeting takes place at home, as interactions can be awkward, involve tension, unease or embarrassment (Bialski, 2018;Miles, 2019;Møller and Petersen, 2017;Race, 2015). There are more serious concerns too: one may be opening themselves up to potential physical harm, property damage, fraud or theft. Letting the stranger in is a highly conditional form of encounter, involving impulse decisions and more deliberate judgements as to who or what types of strangers are seen as desirable and trustworthy. It is evident that many digital applications and platforms are effective in developing new forms of social capital within communities of users. Generalised levels of trust are built through shared experiences, enabled and enhanced by digital systems of shared contacts, user reviews, financial security, and accountability mechanisms that further enhance the prospects for sharing and exchange among groups (cf. Bialski, 2011;Ellison et al., 2007Ellison et al., , 2010. Relations of intimacy among the unacquainted are often (but not always) predicated on processes of exchange and disclosure akin to de-strangering. Knowing someone meaningfully typically requires a feeling of going beyond small talk and engaging in personal dialogue. It often involves developing some background understanding about another person and finding points of commonality or intrigue. Intimacy is never a given, but rather a quality marked by contingency. It emerges as people reciprocate in sharing spaces, stories, feelings and emotions (Germann Molz, 2014;Shah, 2011). When strangers without existing social ties are brought together outside of conventional settings or institutions, encounters are often marked with a sense of freedom and openness (Bialski, 2011(Bialski, , 2012Walsh, 2007). Being in proximate space relatively free from public scrutiny can facilitate intense kinds of engagements, passions and forthright dialogue (Fullagar et al., 2012;Bialski, 2012). Such engagements may encourage a willingness to self-disclose, actively listen and forge connection (Germann Molz, 2012). As Bialski notes, 'people become closer, faster, and often for a very short period of time' (2012: 66). Thus, while stranger intimacies are not uncommon, the affective and emotional intensity they carry can be extraordinary. It is the generative yet conditional nature of stranger intimacy that perhaps most renders it a domain of social relation in need of greater research. As Iveson has argued: '[R]ather than demanding that urban inhabitants be open to encounters with "strangers" we need to learn more about the circumstances in which particular people have taken the risks associated with these stranger encounters and transformed their cities in the process ' (2007: 46).
Commercial transactions often initially underpin encounters involving stranger intimacy. In such cases, the need or desire for personal dialogue and connection may be mitigated. Mechanisms of accountability such as identity verification, rating systems and credit card details are often sufficient for trust to be established and an exchange to proceed (Lynch et al., 2007). Indeed, financially driven meetings between strangers are sometimes not intimate at all: many forms of in-home accommodation involve little interaction with the host. The Alfred Club platform promises zero personal interaction as part of its novelty: subscribers pay for services such as house cleaning, buying groceries and running errands while individual workers are made invisible and interchangeable (Anatoska and Vora, 2015). Reflecting back on Simmel's observations, it is possible to discern how technological change today is contributing to new, ambiguous homecity geographies in which strangers being in one's private space becomes routine, routinely calculated and managed through digital technology (cf. Maalsen, 2020). The flip side of this is that spontaneous public encounters can be drastically diminished or avoided by technology: staring at one's phone substitutes for making small talk, search engines and algorithms replace the need to ask someone for help, and apps can guide pedestrians around areas deemed unsafe or undesirable (Leszczynski, 2016).
Thinking more widely, digitally mediated forms of stranger intimacy or avoidance can be situated within a wider process of boundaryblurring in our contemporary moment taking place between conventional relations of public/private (Koch, 2020;Qian, 2018), and by association between relations such as formal/ informal work (Glucksmann, 2011;Wheeler and Glucksmann, 2014), between producers/ consumers (Bruns, 2010;Ritzler and Jurgenson, 2010) and in terms of social categories such as friend, guest, host or community member. Further, Cockayne et al. (2017) have demonstrated that digital technology can also extend intimacy to the non-or more-thanhuman as people knowingly interact, for example, with robots and algorithms designed to simulate human dialogue in the pursuit of sexual pleasure and fantasy. This parallels work on the role that objects such as the car can play in constituting new forms of relations among unknown others where intimate acts of sharing, caring and even co-ownership emerge (Dowling et al., 2018).
The broad conceptualisation of stranger intimacy we have offered marks out a realm of interaction distinct from the kinds of encounters underpinning much urban and social theory. However, it shares a conceptual concern with geographical questions of bodies, borders and boundaries; with identities, affinities and differences; and with the production of opportunities and inequalities. Examining encounters and interrelated concerns for social connection and capital processes in our contemporary urban world requires a much more robust consideration of how strangers connect through digital technology. Stranger intimacy should also be examined with a resolutely geographical imagination, one that emphasises the importance of understanding locally specific contexts and practices. With these points in mind, we would now like to suggest three principles that any research agenda seeking to explore relations of intimacy, technology and encounter should consider.

Research into stranger intimacies should be avowedly open-ended and attuned to the materialities of practice
This is perhaps a truism for any form of social research. However, new technologies often generate a discourse that oscillates between the celebration of possibility and laments for traditional ways of living being lost. Likewise, new social and economic logics are treated primarily with scepticism by critical scholars seeking to counter the unbridled enthusiasm of entrepreneurs and early adopters. We argue that technologies which facilitate stranger intimacy should not be simplistically understood as eroding or enhancing public life, but rather as tools that help encounters and exchanges happen.
Focusing on questions of practice and consequence -what new technologies or new ways of living do and how they are done -should be the foremost focus of inquiry (cf. Koch, 2015;Valverde, 2003).
Attending in an open-ended way to the socio-materialities of practice can yield surprising and important findings about the way in which technologies create new opportunities and generate new problems. For example, sex and dating apps are frequently vilified in mainstream media for promoting a promiscuous 'hook-up' culture among gay men, increasing unsafe sex practices and negatively impacting queer physical spaces. However, empirical research has demonstrated a more ambivalent landscape. Miles (2017) has found that apps frequently help men better understand their sexuality by enabling them to have discussions with peers online; meanwhile, growing research demonstrates the potential of apps in amplifying health promotion messaging and STI testing (Kesten et al., 2019;Mowlabocus et al., 2016;Rosengren et al., 2016). At the same time, Miles' (2017Miles' ( , 2019 work shows that the way men seeking men use these apps sometimes figures the technologies in question as sources of anxiety, shame and time-wasting, and Chan (2018) finds that the 'networked intimacy' promulgated by location-based media provokes discomfort among gay men deeply involved in the platforms' consumption practices. A key message emerging from both studies is that many users could benefit from more comprehensive induction, education and dialogue in regard to using sex and dating apps so that encounters and interactions are more likely to be positive ones. Further, while app and platform developers are regularly challenged to account for privacy protections, they could also play a greater role in protecting the public from harm on social issues like racism and body shaming. The wider point is that attention to practice in this emerging body of research demonstrates how engaging with technological change in an open-ended way brings forth details and insights often obscured by polarised discourse.
2 Social and spatial differences in how individuals and groups engage in stranger intimacy need to be taken as empirical questions rather than assumed As the ongoing 'digital turn' in geography (Ash et al., 2018) brings greater critical attention to the impacts of digital technology, a key emphasis has been to understand how 'digital divides' relate to existing socio-economic and spatial inequalities (Friemel, 2016;Gonzales, 2016;Ragnedda and Muschert, 2013;Van Dijck, 2011, 2019). This of course provides one starting point for research into technologies of stranger intimacy. Hierarchies of gender, sexuality, ethnicity and physical appearance permeate dating app platforms and re-inscribe biopolitical inequities, as Grindr users can testify having witnessed the pernicious refrain 'no fats, no femmes, no Asians' (Miller, 2015;Ruez, 2016;Shield, 2018). Research into Airbnb in the US has revealed race-based discrimination, with one study revealing that inquirers with African-American sounding names were 16 per cent less likely to be approved (Edelman et al., 2017; see also Griswold, 2018). Sharing economy platforms are generally targeted at urban, middleclass professionals. As with sex and dating apps, the necessity to fit or perform a certain kind of identity means that those who have certain competencies -those who can curate attractive profiles, furnish their home desirably, or are able to fluently converse in the local language -are inherently privileged. Conversely, those who cohabit with others, those outside of city centres, and those with limited access to mobile digital technology or internet data are largely outside of the purview of the imagined app user. While a key promise of the digital is that it can enable people to overcome barriers of place, enabling meaningful relationships to be formed across time and space, the actual practices of using any technology cannot be performed outside of specific cultural contexts and placebased affordances.
However, it should not be assumed that those in particular social groups or geographical locations are not engaging in new kinds of digitally mediated practices that enable them to forge connections, establish trust and develop capital. Those marginalised from more conventional social and economic networks often have much to gain from finding new ways to connect. Compelling research on these points has been developed by Gillespie et al. (2018) who examine smartphone use among Syrian refugees; Graham et al. (2017) who investigate the experience of workers in gig economies across sub-Saharan Africa and South-east Asia; and Madianou and Miller's (2011) research on transnational domestic service workers using social media to build and maintain intimate relations. One important strand of inquiry would be to assess different usage rates of digital platforms by different demographic groups, split for example by ethnicity, age, gender or socio-economic class. One's social position may affect not only their access to networks and resources, but also the circumstances in which they are willing to trust unknown others. Here, Ettlinger's (2003) arguments for dehomogenising relations of trust provide a useful starting point for untangling the different rationalities and affective forces that shape interactions not only among different spheres of personal and public life, but also among individuals and groups of different social position, and among communities of trust that can be local or non-localised. Building on 'ethnographies of encounter' (Faier and Rofel, 2014) in anthropology, scholars might also explore how members from different cultural backgrounds or with unequal stakes in the relationships negotiate stranger intimacies (see also Beban and Schoenberger, 2019). In contexts where platforms are proliferating, smartphone ownership is dramatically rising and internet data is becoming much more available and affordable, it remains to be seen how hierarchies of opportunity and privilege are reinforced or reconfigured.
3 New technologies interact dynamically with prevailing social and economic logics. Geographers will need to engage ethnographically and beyond to understand ongoing changes in stranger intimacy and their collective effects Our perspective is undoubtedly partial, but living in London we personally inhabit a world in which our friends, neighbours and colleagues have grown comfortable with stranger intimacies that would have seemed unusual in the recent past. App-based dating is the norm, the short-term letting of one's home is common, and almost no one thinks twice about getting into a stranger's car hailed via smartphone. Digital technology has helped to mitigate risks, but it has also changed the way people think and behave. The sociality of sex and dating has shifted such that many people are reluctant to approach someone in public for fear of rejection or embarrassment, yet are quite comfortable having intimate conversations online, discussing sexual preferences, sharing private photos and arranging at-home meetings. Logics of property and tenure are changing too. Digital platforms help many Londoners cope with costs of living, but they also promote new kinds of entrepreneurialism and rent-seeking. A spare room, a holiday away from the city, or a long solo car ride increasingly becomes seen as an opportunity for making money.
To understand the cultural and socioeconomic changes being brought about by new forms of stranger intimacy, ethnographic insights are essential. They reveal the kinds of opportunities and rewards being pursued, as well as the values and judgements underpinning how boundaries are drawn and negotiated. Ethnography also helps get at practical knowledge involved in using particular apps and platforms, and it is useful for examining how practices evolve as technology develops alongside changing norms and conventions. Yet doing ethnography on digitally mediated encounters can be difficult, as much of the interaction takes place on screens and/or in relative privacy. Emerging conversations about 'digital ethnography' (Duggan, 2017;Hjorth et al., 2017) offer some productive pathways into such terrain, but it is also important to emphasise that 'the digital' should not be consigned to an isolated field of practice, nor to a distinct disciplinary subfield (Ash et al., 2018). It will also be crucial that geographers examine stranger intimacies beyond their own cultural contexts. This will involve significant challenges in terms of negotiating access, working ethically, and navigating insider/outsider positionalities (cf. Campbell et al., 2006;Mohammad, 2001) to learn about qualitative similarities and differences in how encounters are brokered, and to what ends.
However, to understand broader collective effects of stranger intimacies, particularly at the urban scale, there is also a pressing need to incorporate forms of analysis that go beyond ethnographic understanding. Returning back to our home city of London, for example, we might begin to ask about the effects that stranger intimacies are having on the spaces where people conventionally meet. What is the relation between digitally mediated sociality and the decline in nightlife venues generally, and LGBTQþ spaces specifically (Campkin and Marshall, 2018)? What is the correlation between digital platforms such as Airbnb and patterns of gentrification (cf. Wachsmuth and Weisler, 2018)? How do automobile and ridesharing apps impact public transportation use (Shaheen and Cohen, 2018) and car ownership (Kamargianni et al., 2018)? Bringing qualitative understandings into engagement with more quantitative and GIS-based approaches can make use of available data to help to visualise and more systematically analyse patterns of app and platform use. Such insights can also help to inform policy debates about interventions that can effectively mitigate against collective harms.

V Conclusion
Questions of how unknown others encounter and relate to one another have long been a central concern in social and urban theory. Processes of urbanisation and globalisation accelerated forms of mobility and communication, and the production of novel spaces for work, leisure, consumption and transport have all provided fertile ground for theorising and empirically examining interactions among strangers. Yet the impacts that digital technologies are having on patterns of sociality and exchange have yet to be adequately incorporated into geographical scholarship, particularly in research focused specifically on encounter. This is striking given that Simmel's foundational work on encounter compellingly emphasised how earlier forms of technologyindustrial production, railway transportation and timekeeping -profoundly impacted the interpersonal dynamics and subjective experiences of life among strangers. Likewise, the highly influential work on stranger relations and public culture by scholars like Habermas and Sennett was grounded in registering the effects of socio-technological change. Today, smartphones and tablets, digital platforms and software applications, GPS and location-based media are reshaping how stranger encounters happen, as the digital renders ambiguous many distinctions between proximity and distance, connection and disconnection, human and non-human (Richardson, 2016). These technologies and the new social and economic logics in which they are entwined should be part and parcel of any research into how people live and relate today.
Focusing on intimate forms of stranger encounter, this paper has outlined various ways in which digital technology helps to bring unknown others together for shared pleasures and economic and cultural pursuits. It has outlined how digitally mediated practices including searching, scoping, screening and selecting facilitate meetings among individuals in ways that reconfigure both space and time. It has also detailed how trust and a sense of accountability are established, through formal means such as identity checks and credit card verification and through interpersonal dialogue, that help to establish shared understandings and points of connection. The shift from stranger encounters in contemporary cities being as much about choice as they are chance generates several critical considerations. New forms of exclusiveness, selectivity and social distancing brought into being by these technologies and practices need to be better understood. So too do the ways in which they facilitate and enable people to engage in relations of knowing, caring, befriending and loving, particularly outside of conventional institutions and networks of sociality. As new forms of segregation and social distancing are continuously pioneered (Atkinson, 2016;Chronopoulos, 2012;Minton, 2012), understanding the ways in which people come together in mutually beneficial ways is a matter of critical importance.
The COVID-19 pandemic has brought extraordinary disruption and fraught intensity to many interpersonal encounters. Physical proximity is potentially life-threatening and unprecedented forms of social distancing have come into being. Digital technology has proven essential to how people stay in touch with family, friends and colleagues and has supported people in connecting locally and globally with unknown others for acts of care, solidarity, conversation, entertainment and intimacy. At the same time, the pandemic has exposed differences and exacerbated precisely the kinds of inequalities this paper has sought to foreground. Beyond the most urgent moments of crisis, the pandemic will undoubtedly result in enduring changes to the behavioural, biopolitical and affective forces through which strangers are judged and encounter is negotiated.
Our hope in outlining an agenda for further research on stranger intimacies is threefold. We believe firstly that a nuanced understanding of how digital technology connects people or holds them apart can contribute to the development of better platforms, apps and devices. Developers and designers should be continuously challenged to innovate, not only for the sake of novelty or profit, but also for equity and empowerment. Second, where this fails or when collective harms of new digitally mediated practices are identified, practical insights garnered through sustained, critical research help to inform ideas and decision-making about interventions, be they governmental, corporate or user-generated (Arora and Scheiber, 2017). Third and finally, we believe that research can help individuals and groups become more competent users of new technologies, enabling them to form meaningful and mutually beneficial connections with others. In these ways, the hopeful possibilities of urban life as a gathering of strangers might be realised.

Declaration of conflicting interests
The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Funding
The author(s) received no financial support for the research, authorship, and/or publication of this article.