Self-presentation undergirds social interaction on social media. HCI and social computing scholarship draw on visibility to theorize self-presentation management; while research addresses how social media users leverage (in)visibility for self-presentation goals, how users perceive and assess the visibility of themselves and others merits investigation. We conducted interviews ( \(n=20\) ) to explore how U.S.-based social media users perceive and assess self visibility. Findings indicate that self visibility comprises a set of related objects’ visibility—content, persons, and identity—associated with distinct, but related, visibility attributes. We develop the visibility objects lens to examine self-presentation, contributing a unified social media visibility framework. We show how users perceive themselves as visible to platforms and algorithms, which act as visibility agents. We introduce reflected algorithmic visibility to describe awareness of visibility to platforms and algorithms informed by algorithmic feedback. We conclude with design implications of a visibility objects lens.

Algorithmic systems have infiltrated many aspects of our society, mundane to high-stakes, and can lead to algorithmic harms known as representational and allocative. In this paper, we consider what stigma theory illuminates about mechanisms leading to algorithmic harms in algorithmic assemblages. We apply the four stigma elements (i.e., labeling, stereotyping, separation, status loss/discrimination) outlined in sociological stigma theories to algorithmic assemblages in two contexts : 1) "risk prediction" algorithms in higher education, and 2) suicidal expression and ideation detection on social media. We contribute the novel theoretical conceptualization of algorithmic stigmatization as a sociotechnical mechanism that leads to a unique kind of algorithmic harm: algorithmic stigma. Theorizing algorithmic stigmatization aids in identifying theoretically-driven points of intervention to mitigate and/or repair algorithmic stigma. While prior theorizations reveal how stigma governs socially and spatially, this work illustrates how stigma governs sociotechnically.

Vulnerability intimately shapes the lived human experience and continues to gain attention in computer-supported cooperative work and human-computer interaction scholarship broadly, and in social media studies specifically. Social media comprise sociotechnical affordances that may uniquely shape lived experiences with vulnerability, rendering existing frameworks inadequate for comprehensive examinations of vulnerability as mediated on social media. Through interviews with social media users in the United States (N = 20) and drawing on feminist conceptualizations of vulnerability and social media disclosure and privacy scholarship, we propose a feminist taxonomy of social media vulnerability (FSMV). The FSMV taxonomy reflects vulnerabilitysources, states, andvalences, within which we introduce the state ofnetworked vulnerability andambivalent, desired, andundesired valences. We describe how social media enable forms of vulnerability different from in-person settings, challenge framings that synonymize vulnerability with risk/harm, and facilitate interdisciplinary theory-building. Additionally, we discuss hownetworked, ambivalent, andun/desired vulnerability extend and diverge from prior work to create a theoretically rich taxonomy that is useful for future work on social media and vulnerability. Finally, we discuss implications for design related to granular control over profile, content, and privacy settings, as well as implications for platform accountability, as they pertain to social media vulnerability.

Social comparison and social support have implications for individuals' wellbeing, offline and on social media. Perceptions of similarity underlie both social comparison and social support processes, though how comparison and support function in tandem in online spaces, and which aspects of identity and experiential similarity are salient to which comparison and support outcomes, merits investigation. Through interviews with people who have joined or considered joining social media-based support groups following pregnancy loss (N=18), we provide an intracommunity view into social comparison within online support groups. We identify a set of identity and experience attributes that inform perceptions of similarity and difference in these support spaces. We characterize tensions arising from these attributes and propose the preliminary Social Comparison and Social Support in Online Support Groups model to describe interactions between social support and comparison processes within online support groups. We further discuss findings' implications for design, including via introducing the tolerance principle of online health support groups. CAUTION: This paper includes quotes about pregnancy loss.

Authenticity, generally regarded as coherence between one's inner self and outward behavior, is associated with myriad social values (e.g., integrity) and beneficial outcomes, such as psychological well-being. Scholarship suggests, however, that behaving authentically online is complicated by self-presentation norms that make it difficult to present a complex self as well as encourage sharing positive emotions and facets of self and discourage sharing difficult emotions. In this paper, we position authenticity as a self-presentation norm and identify the sociomaterial factors that contribute to the learning, enactment, and enforcement of authenticity on the short-video sharing platform TikTok. We draw on interviews with 15 U.S. TikTok users to argue that normative authenticity and understanding of TikTok as a "fun" platform are mutually constitutive in supporting a "just be you" attitude on TikTok that in turn normalizes expressions of both positive and difficult emotions and experiences. We consider the social context of TikTok and use an affordance lens to identify anonymity, of oneself and one's audience; association between content and the "For You" landing page; and video modality of TikTok as factors informing authenticity as a self-presentation norm. We argue that these factors similarly contribute to TikTok's viability as a space for social support exchange and address the utility of the comments section as a site for both supportive communication and norm judgment and enforcement. We conclude by considering the limitations of authenticity as social norm and present implications for designing online spaces for social support and connection.