Project Xanadu

Project Xanadu was the first hypertext project, founded in 1960 by Ted Nelson. Administrators of Project Xanadu have declared it an improvement over the World Wide Web, with mission statement: "Today's popular software simulates paper. The World Wide Web (another imitation of paper) trivialises our original hypertext model with one-way ever-breaking links and no management of version or contents."

Wired magazine published an article called "The Curse of Xanadu", calling Project Xanadu "the longest-running vaporware story in the history of the computer industry". The first attempt at implementation began in 1960, but it was not until 1998 that an – incomplete – implementation was released. A version described as "a working deliverable", OpenXanadu, was made available in 2014.

Nelson's vision was for a "digital repository scheme for world-wide electronic publishing". Nelson states that the idea began in 1960, when he was a student at Harvard University. He proposed a machine-language program which would store and display documents, together with the ability to perform edits. This was different from a word processor (which was not invented yet) in that the functionality would have included visual comparisons of different versions of the document, a concept Nelson would later call "intercomparison".

On top of this basic idea, Nelson wanted to facilitate nonsequential writing, in which the reader could choose his or her own path through an electronic document. He built upon this idea in a paper to the ACM in 1965, calling the new idea "zippered lists". These zippered lists would allow compound documents to be formed from pieces of other documents, a concept named transclusion. In 1967, while working for Harcourt, Brace, he named his project Xanadu, in honour of the poem "Kubla Khan" by Samuel Taylor Coleridge.

Nelson's talk at the ACM predicted many of the features of today's hypertext systems, but at the time, his ideas had little impact. Though researchers were intrigued by his ideas, Nelson lacked the technical knowledge to demonstrate that the ideas could be implemented.

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