This document discusses how librarians can use social networking and Web 2.0 tools to engage modern library users and extend readers services in the 21st century. It finds that a large portion of library users are active on social media platforms. The document then outlines various social networking sites and tools like blogs, wikis, Flickr, and video sharing and provides examples of how libraries have used these tools for activities like marketing, outreach, and reference services. It also discusses best practices and potential risks of using social media in libraries.