This article examines how civic technologists understand and use data to facilitate civic engagement. It illustrates the cultural and historical situatedness of data affordances and shows how civic technologists think of themselves as facilitators of civic engagement: they use and understand data in ways that are supposed to expand the agency of publics towards governments. The article shows how civic technologists use data to implement a form of participatory culture in new ways, and contributes to our understanding of how datafication enables new forms of activism.