The document categorizes 165 Web 2.0 tools into 20 categories including blogging, chat, charts & graphs, file sharing, microblogging, notebooks, online office suites, online presentations, personal web portals, photo editing/sharing, search engines, social bookmarking, social networks, surveys & polling, task & group management, video chat, video editing/sharing, website creation, wikis, and group template pages. Each category lists several relevant tools.