Social bookmarking allows users to access bookmarks from any computer, store bookmarks in a centralized location organized by project or topic, and share bookmarks with other researchers or students engaged in related work. Common social bookmarking sites include Diigo and Delicious, which allow users to comment on websites and documents, receive emails when group members add bookmarks, and view bookmarks and annotations from others. Social bookmarking can help students and researchers stay up to date with resources others have found useful and provide annotations on those resources.