Ethan Todras-Whitehill writes: "Networking sites on the Web started as online personal ads, and most are still built around the desire to meet people. But there is a new, rapidly growing generation of networking sites built around purposes, not people. ¶ These sites connect people by their interests and goals. Three such sites are del.icio.us, which lets users bookmark Web sites and share the bookmarks with others; 43things.com, which loosely connects users with shared goals like learning to play the guitar; and PledgeBank.com, a London-based nonprofit site that brings users together to participate in civic actions, like starting a political group or giving blood. ...¶... Until recently, however, groups needed a critical mass to have such a Web presence, and finding them could be difficult. Idea- and activity-oriented networking sites create ad hoc homes for many small groups and interests, and make them more easily accessible. ¶ The form of information classification used on del.icio.us has become known as "folksonomy," a play on the word "taxonomy," coined by Thomas Vander Wal, a Web production manager who is an avid user of del.icio.us. ..." Link: New York Times.