This paper explores the implications of Zeynep Tufekci’s capacities approach to social movements, which explains the strength of social movements in terms of their capacities. Tufekci emphasises that the capacities of contemporary social movements largely depend upon their uses of new digital technologies, and of social media in particular. We show that Tufekci’s approach has important implications for the structure of social movements, whether and what obligations they can have, and for how these obligations distribute to their members. In exploring (...) these implications, we develop a tripartite taxonomy of social movements. Each type of social movement in the taxonomy corresponds to a different type of group: social campaigns, social struggles, and social agitations. We show that all three types of social movement can bear obligations in virtue of their capacities. Finally, we argue that a surprising upshot of the obligations of social movements is that members of oppressed groups can have obligations to resist their own oppression in virtue of being members of social movements. (shrink)