This document discusses various social media and networking sites and tools that allow users to connect and share information online. It outlines the types of sites, including those for blogging, message boards, bookmarking, wikis, and social networks. Some key points made are that social networks enable grassroots sharing of user-generated content and experiences, information spread rapidly through social networks can be credible, and building links from other sites can help increase a site's popularity and allow for research.