  Online communities can serve as meaningful sources of social support,
particularly for marginalized and vulnerable groups. Disclosure of personal
information facilitates integration into online communities but may also expose
individuals to harm, including cyberbullying and manipulation. To better
understand negative user experiences resulting from self-disclosure in online
conversations, we interviewed 25 participants from target populations on
Reddit. Through thematic analysis, we outline the harm they experience,
including damage to self- and group identities. We find that encountering
online harm can worsen offline adversity. We discuss how users protect
themselves and recover from harm in the context of current platform
affordances, highlighting ongoing challenges. Finally, we explore design
implications for a community-driven, bottom-up approach to enhance user
well-being and safety.
