This dissertation develops a design framework for friendship-supportive youth social media. I conducted a qualitative meta-analysis across my formative, case-study, and co-design work with teens and young adults, synthesizing recurring design themes into three pillars: social understanding (legible norms, intentions, trust, reciprocity, and accountability), placeness (spatial and embodied affordances that make online interaction feel inhabitable), and identity alignment (authentic expression that remains current, plural, and interpretable). The framework is grounded in interpersonal, developmental, and sociotechnical theory, but its contribution is design-oriented: it translates broader accounts of friendship and social development into the specific ways social media platforms can shape youth friendship building. I initially validate parts of this framework through WhoamI Today (WIT), a platform deployed with 99 youth across the United States and Korea. My proposed work extends this validation through a follow-up deployment while refining the framework as a roadmap for cumulative design research on youth social media.

Children today encounter social issues—climate change, conflict, inequality—through digital technologies, and the design of that encounter shapes whether young people move toward lasting civic engagement or toward anxiety and withdrawal. Much of the content children see is optimized for attention through fear and urgency, with few pathways toward meaningful action—contributing to rising distress and disengagement among young people who care deeply but feel powerless to act. This half-day workshop introduces “sustainable care” as a design lens, asking how technology might support children’s sustained engagement with social causes without contributing to empathic distress or burnout. We invite researchers and practitioners across child-computer interaction, games, education, and youth mental health to map this landscape together and develop a research agenda for the CCI community.

We present a design framework for friendship-supportive youth social media, derived from a synthesis of five empirical studies with 331 youth participants (ages 13–25) using interviews, co-design, surveys, diary studies, and a field deployment. Iterative analysis of 209 design-relevant data points identified three pillars: Social Understanding (interaction norms, interaction cues and scaffolding, social accountability and governance), Placeness (third place and community, boundaries and personal spaces, shared presence), and Identity Alignment (identity currency, identity plurality, relational identity signals). The framework maps nine design spaces through which platforms can support the conditions under which youth friendships form, deepen, and are maintained. It offers a shared vocabulary for locating contributions, comparing design interventions, and identifying under-explored areas for future work.

Through co-design interviews (N=19) and a design evaluation survey (N=136) with U.S. teens ages 13-18, we investigated teens' privacy management on social media. Our study revealed that 28.1% of teens with public accounts and 15.3% with private accounts experience dysfunctional fear, that is, fear that diminishes their quality of life or paralyzes them from taking necessary precautions. These fears fall into three categories: fear of uncontrolled audience reach, fear of online hostility, and fear of personal privacy missteps. While current approaches often emphasize individual vigilance and restrictive measures, our findings show this can paradoxically lead teens to either withdraw from beneficial social interactions or resign themselves to accept privacy violations, viewing them as inevitable. Drawing on teen input, we developed and evaluated ten design prototypes that emphasize empowerment over fear, system-wide explicit emphasis on privacy, clear privacy norms, and flexible controls. Survey results indicate teens perceive these approaches as effectively reducing privacy concerns while preserving social benefits. Our findings suggest that platforms will be more likely to protect teens' privacy and less likely to manufacture unnecessary fear if they include designs that minimize the impact on other users, have low trade-offs with existing features, require minimal user effort, and function independently of community behavior. Such designs include: 1) alerting users about potentially unintentional personal information disclosure and 2) following up on user reports.

Women face significant challenges in seeking support for sexual and reproductive health (SRH) due to cultural taboos and microaggressions, even within supposedly safe online spaces. This study focuses on unmarried South Korean women who encounter these difficulties and often risk detrimental health outcomes by avoiding timely care. To investigate how to create safer and more supportive spaces for these women, we designed a 9-week study using the Asynchronous Remote Communities method for 26 unmarried Korean women participants. We created structured and unstructured activities to encourage sharing SRH narratives, which led to increased mutual support and understanding among participants. Additionally, we designed educational and reflective interventions that helped participants recognize the nuances and harms of microaggressions. This increased awareness promoted self-reflection and supportive actions among participants. Our approach demonstrates the potential to create supportive, reflective online spaces for people from marginalized communities who face stigmatized healthcare challenges. We hope our research inspires the development of more inclusive online spaces, driving positive social change in stigmatized healthcare support.

Platforms like Nextdoor and Citizen can increase users’ fear of crime by broadcasting frequent, local, and personalized information about potential safety risks. These platforms can contribute to a dysfunctional fear of crime, which undermines a person’s quality of life and mental health without actually making them feel safer. In this work, we conducted a mixed-methods study to understand the potential for design to foster a functional fear of crime, which motivates precaution without negatively impacting quality of life. We first interview individuals with a dysfunctional fear of crime and then validate interview results with a survey. Through this process, we identified five strategies for designers to support users in developing a more functional fear of crime. These strategies surface overarching theoretical and design implications for designers and researchers of safety platform with the ultimate goal of supporting safety, quality of life, and mental health for users of these platforms.

Prior research links teens’ social media use to a reduction in their sense of well-being. The current study investigates how design mediates this link, with an overarching goal of designing better social media experiences for teens. We conducted a mixed-method study with teens (N=25, Mage= 16.5 years) to investigate their moment-by-moment experiences and emotional states while using Instagram. Our analysis showed that teens’ experiences on Instagram often entailed sifting through a content soup dominated by uninteresting, irrelevant content. Boredom served as a reason to enter Instagram, a justification to leave, and as a dominant feeling during a session. The promise of social connection was the main motivator for teens to use Instagram. Teens developed strategies to maintain a state of emotional equilibrium as they sought moments of connection with friends: (1) Feed gatekeeping, (2) Backpedaling away from negative content, (3) Choosing to hide like-counts, and (4) Avoiding notification whiplash.

Adolescents are particularly vulnerable to the pressures created by social media, such as heightened self-consciousness and the need for extensive self-presentation. In this study, we investigate how BeReal, a social media platform designed to counter some of these pressures, influences adolescents' self-presentation behaviors. We interviewed 29 users aged 13-18 to understand their experiences with BeReal. We found that BeReal's design focuses on spontaneous sharing, including randomly timed daily notifications and reciprocal posting, discourages staged posts, encourages careful curation of the audience, and reduces pressure on self-presentation. The space created by BeReal offers benefits such as validating an unfiltered life and reframing social comparison, but its approach to self-presentation is sometimes perceived as limited or unappealing and, at times, even toxic. Drawing on this empirical data, we propose design guidelines for platforms that support authentic self-presentation while fostering reciprocity and expanding beyond spontaneous photo-sharing. These guidelines aim to enable users to portray themselves more comprehensively and accurately, ultimately supporting teens' developmental needs, particularly in building authentic relationships.