The authors aim at illuminating several fundamental and powerful yet theoretically obscure aspects of collective actions in social media. The reader will gain an advanced and deepen our understanding of collective action in the new generation of (ICT) enabled by Web 2.0, also referred to as social media, to help critical decision and policy making. The developed theories will be a valuable and comprehensive reference for those interested in newer Information and Communication Technologies (ICTs), in examining their role in decision and policy making, understanding the dynamics of interaction, communication, and information propagation, and researching in social networks for years to come. This interdisciplinary work is the result of researchers, practitioners, working in computer science, sociology, behavioral science, psychology, cultural study, information systems, operations research and communication, and methodologies research. The researchers present their new concepts, ideas, principles, and methodologies, aiming to advance and deepen our understanding of collective action in social media to help critical decision and policy making.