Ted Nelson has been on my mind a lot this year. Nelson was a pioneer in computing, and in 1965 he coined the word hypertext as part of the project that would define his career: Project Xanadu . With Xanadu, he had a specific vision of what computing could be, which he called the docuverse . He imagined a system that could keep every version of a document; hypertext links would know both their source and destination, and quotations would be kept by reference (rather than copy) so any included text maintained its identity and source. Everything, in this version of computing, would be intertwingled and xanalogical . We're talking about attribution down to the span. To be xanalogical is to follow two rules: Never copy, always reference (also known by a Nelsonism, transclusion ). Never overwrite, always version. As Nelson designed it, Xanadu would manage the system's complexity and massive bookkeeping burden itself, so users only experienced the benefits of a system that could never forget.…