Every once in a while I see references to Xanadu, as a solution that would fix all of the problems with current WWW by making broken links impossible. At some p

Every once in a while I see references to Xanadu, as a solution that would fix all of the problems with current WWW by making broken links impossible. At some point, I spent some time reading about Xanadu's protocol, and I now think it would never work at all, since it makes some pretty wide assumptions: Xanadu assumes that documents are stored on append-only structure: they never disappear, and instead of updating the document, one just publishes a new version (with all the text from the previous ones was still available). See for example http://www.xanadu.com.au/ted/XUsurvey/xuDation.html http://www.xanadu.com.au/ted/XUsurvey/xuDation.html figures 9/10 and then figure 16. Later, there is a reference to cache, but with no details whatsoever: "... content may be cached in many places, as long as it has the same permanent IDs..." I have no idea how is this supposed work in the real life. Today, the static web hosting is dirt cheap, but back in 90's it was $20/mo for just a few megabytes. In a Xanadu world, what would happen once you no longer pay for service?