In the landscape of online social networking sites, many platforms are reaching a scale and longevity that require designers to address the postmortem data interactions that follow people’s deaths. To evaluate the experiences and challenges people face when caring for memorialized profiles, we conducted 28 qualitative interviews with people serving as legacy contacts for memorialized Facebook accounts. We report on who legacy contacts are and their practices and their expectations, and find that people were chosen to be a legacy contact for one major reason: trust. In our analysis, we find disconnects between how people understand trust in the context of interpersonal relationships and how trust is technically implemented. We conclude by discussing the persistent challenges of representing the ambiguity of interpersonal trust in impersonal, computational systems.