Social computing refers to the endeavor to understand complex human interactions in social media like blogs, friendship networks, wikis, social bookmarks (folksonomies), and online media sharing through computational means. Research in social computing builds on participatory Web characterized by Rich Internet Applications, user generated-enriched content, user developed widgets, and collaborative environment of citizen journalism. Social computing is a vibrant and fledgling field with many research challenges including data deluge, dynamism, long tail phenomenon, sparse link structure, lack of ground truth, information quality, and data collection. This book presents research towards these challenges motivated by the need for identifying influential bloggers, extracting clusters, and searching for familiar-strangers in egocentric networks. Novel solutions using network and content information, dynamic collective wisdom, social identity based on group affiliations, and providing evaluation frameworks leveraging the power of social media are presented aiming at understanding individuals, communities and their interactions, paving the way for further research and development.