Digital participatory platforms like Wikipedia are often celebrated as projects that allow anyone to contribute. Any user can sign up and start contributing immediately. Similarly, projects that engage volunteers in the production of scientific knowledge create easy points of entry to make contributions. These low barriers to entry are a hallmark…

Recent advances in interactive web technologies, combined with widespread broadband and mobile device adoption, have made online collective action commonplace. Millions of individuals work together to aggregate, annotate, and share digital text, audio, images, and video. Given the prevalence and importance of online collective action systems,…