This document discusses the concept of Library 2.0 and how libraries are adopting technologies associated with Web 2.0 to become more user-centered and participatory. It defines key terms like blogs, wikis, folksonomy/tagging, RSS, social bookmarking, mashups and describes how libraries are using these tools. Examples are provided of libraries using social networking sites, photo sharing, video streaming, tagging systems and more to engage users and adapt to Web 2.0 principles of interactivity and user participation.