CSCW researchers have become interested in crowd work as a new form of collaborative engagement, that is, as a new way in which people's actions are coordinated in order to achieve collective effects. We address this area but from a different perspective - that of the labor practices involved in taking crowd work as a form of work. Using empirical materials from a study of ride-sharing, we draw inspiration from studies of the immaterial forms of labor and alternate analyses of political economy that can cast a new light on the context of crowd labor that might matter for CSCW researchers.