Extremely volatile hypertexts
Constructive frameworks (MacWeb)
Literary machines that learn
Hypertext with characters
Much interesting systems work involves extremely volatile hypertexts.
Sometimes, these are volatile because several people are writing them at once -- at the same time you're reading them.
Sometimes, they're volatile because the machine responds to your changes with more changes. Or the document learns inductively from the work you do.
Sometimes, they're volatile because they're moody.