An amazing Web 2.0 application: TiddlyWiki.

It is indeed cool, the only problem could be this is too cool for the average Joe. You need to learn a bit in order to use it, I'm afraid there will be some people who will not be able to climb that high and give up.

The other problem is lynx is useless for these kind of pages. Pages with some moderate amount of "web 2.0" are still OK with links; this one is totally not OK.