In our paper for the ICA 2014 preconference on Sharing, Kristen Barta and I show how the Quantified Self community mobilizes the technological and social platforms for sharing and building social capital. The paradox is that online sharing in this community both extends what happens in the in-person local MeetUps while it establishes the boundaries of the community. There’s a relative ambiguity of what is valued in the community that is managed through sharing. Is it personal stories and histories, cool new technologies, or sharable new innovations for tracking that can be adapted by others? QS structures their presentations through three questions that help the community get around these different values and in turn manage what different people look for from the QS community. This is, we argue, a model for studying the so-called sharing economy. In particular our preliminary study shows how the platforms of sharing provide the affordances and constraints that shape how people approach sharing and how people benefit from sharing.