The World Wide Web ("WWW" or simply the "Web") is a global information medium which users can read and write via computersconnected to the Internet. The term is often mistakenly used as a synonym for the Internet itself, but the Web is a service that operates over the Internet, just as e-mail also does. The history of the Internet dates back significantly further than that of the World Wide Web.The hypertext portion of the Web in particular has an intricate intellectual history; notable influences and precursors include Vannevar Bush'sMemex,[1] IBM's Generalized Markup Language,[2] and Ted Nelson's Project Xanadu.[1]The concept of a home-based global information system goes at least as far back as "A Logic Named Joe", a 1946 short story by Murray Leinster, in which computer terminals, called "logics," were in every home. Although the computer system in the story is centralized, the story captures some of the feeling of the ubiquitous information explosion driven by the Web.