In recent years, community platforms that pertain to the emerging class of social software have gained considerable popularity among lead users on the Web. Such Web 2.0 platforms focus on supporting information exchange in online social networks by providing services for information search, publication and sharing, and collaborative classification of personal information in individual users' social contexts represented by co-workers, friends or family members. Since functional features and information models of social software reveal limitations from the individual user's perspective, the user-centered social software model proposes an integrated view on all available information by encompassing services for the acquisition of relevant information, controlled information dissemination to selected contacts and flexible metadata and semantic information relation management concerning the organization of distributed personal information. The intended audience of this book are community members, knowledge workers and researchers who are interested in gaining an insight into the characteristics of social software and support of personal information management in online social networks.