Examples of Social Bookmarking websitesSocial bookmarking is a method for Internet  users to share, organize, search, and manage bookmarks of web resources.

In a social bookmarking system, users save links to web pages that they want to remember and/or share. These bookmarks are usually public, and can be saved privately, shared only with specified people or groups, shared only inside certain networks, or another combination of public and private domains. The allowed people can usually view these bookmarks chronologically, by category or tags, or via a search engine.

Many social bookmarking services provide web feeds for their lists of bookmarks, including lists organized by tags.  This allows subscribers to become aware of new bookmarks as they are saved, shared, and tagged by other users.

As these services have matured and grown more popular, they have added extra features such as ratings and comments on bookmarks, the ability to import and export bookmarks from browsers, emailing of bookmarks, web annotation, and groups or other social network features.

Source:  Wikipedia.   Read more @ http://en.wikipedia.org/wiki/Social_bookmarking