The document discusses social bookmarking and annotation tools. It begins by defining social bookmarking as a method for sharing, organizing, searching and managing bookmarks of web resources through online services, allowing users to access bookmarks from any computer. It notes that social bookmarking services allow tagging resources with keywords to describe them and sharing bookmarks with other users. The document then defines annotation as adding comments or notes to resources to discuss their contents, such as using sticky notes or highlighting text. It proceeds to provide details about using the social bookmarking tool Diigo, including signing up for accounts and installing its toolbar browser extension.