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.
Most social bookmark services encourage users to organize their bookmarks with informal tags instead of the traditional browser-based system of folders, although some services feature categories/folders or a combination of folders and tags. They also enable viewing bookmarks associated with a chosen tag, and include information about the number of users who have bookmarked them. Some social bookmarking services also draw inferences from the relationship of tags to create clusters of tags or bookmarks.
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.
Founded in 2003, del.icio.us pioneered tagging and coined the term social bookmarking. In 2004, as del.icio.us began to take off, Furl and Simpy were released, along with Citeulike and Connotea (sometimes called social citation services), and the related recommendation system Stumbleupon. In 2006, Ma.gnolia, Blue Dot, and Diigo entered the bookmarking field, and Connectbeam included a social bookmarking and tagging service aimed at businesses and enterprises. In 2007, IBM released its Lotus Connections product.
Sites such as Digg, reddit, and Newsvine offer a similar system for organization of "social news".
For users, social bookmarking can be useful as a way to access a consolidated set of bookmarks from various computers, organize large numbers of bookmarks, and share bookmarks with contacts. Libraries have found social bookmarking to be useful as an easy way to provide lists of informative links to patrons.
Social bookmarking can also be susceptible to corruption and collusion. Due to its popularity, some users have started considering it as a tool to use along with search engine optimization to make their website more visible. The more often a web page is submitted and tagged, the better chance it has of being found. Spammers have started bookmarking the same web page multiple times and/or tagging each page of their web site using a lot of popular tags, obliging developers to constantly adjust their security system to overcome abuses.