This book constitutes the proceedings of the 5th International Conference on Social Informatics, SocInfo 2013, held in Kyoto, Japan, in November 2013. The 23 full papers, 15 short papers and three poster papers included in this volume were carefully reviewed and selected from 103 submissions. The papers present original research work on studying the interplay between socially-centric platforms and social phenomena.

Challenging the notion that digital media render traditional, formal organizations irrelevant, this book offers a new theory of collective action and organizing. Based on extensive surveys and interviews with members of three influential and distinctive organizations in the United States - The American Legion, AARP, and MoveOn - the authors reconceptualize collective action as a phenomenon in which technology enhances people s ability to cross boundaries in order to interact with one another and engage with organizations. By developing a theory of Collective Action Space, Bimber, Flanagin, and Stohl explore how people's attitudes, behaviors, motivations, goals, and digital media use are related to their organizational involvement. They find that using technology does not necessarily make people more likely to act collectively, but contributes to a diversity of participatory styles, which hinge on people s interaction with one another and the extent to which they shape organizational agendas. In the digital media age, organizations do not simply recruit people into roles, they provide contexts in which people are able to construct their own collective experiences.