Social bookmarking is the practice of saving bookmarks to a public Web site and “tagging” them with keywords. Bookmarking, on the other hand, is the practice of saving the address of a Web site you wish to visit in the future on your computer. To create a collection of social bookmarks, you register with a social bookmarking site, which lets you store bookmarks, add tags of your choice, and designate individual bookmarks as public or private.
Some sites periodically verify that bookmarks still work, notifying users when a URL no longer functions. Visitors to social bookmarking sites can search for resources by keyword, person, or popularity and see the public bookmarks, tags, and classification schemes that registered users have created and saved.