Social bookmarking allows internet users to store, organize, search, and share bookmarks of web pages. Users can bookmark pages using popular tools like Delicious or StumbleUpon. Bookmarks are usually public but can be private, and users can share bookmarks with their network. Users assign tags or keywords to bookmarks to classify and search them. Social bookmarking ranks pages based on how often they are bookmarked rather than external links, and can surface pages not indexed by search engines. While easy to use, social bookmarking has drawbacks like lack of tagging standards and potential for spam.