I checked out TiddlyWiki
a while ago, after Ned Batchelder
wrote about it. Since then, I've been trying to use it to contain my todo lists, which usually end up living in multiple Notepad files on the desktop. So far I'm having mixed success because I'm so used to using Notepad, however that's not to say that TiddlyWiki isn't impressive and useful, because it is. Anyway, Jeremy Ruston is continuing to make some great updates to the project - I won't bother listing all the individual updates as they're easy to find on the homepage, however category style tags, updated RSS support, and some new display options are all very welcome additions.
There's also some new adaptions out there, including an Encrypted version. The PHP version is making me wonder whether there'd be any demand out there for a Domino TiddlyWiki.