Matt Mower points to Socialtext, a new company made up of a few names that I keep seeing attached to things in the 'social software' world and around the Topic Exchange. No apparent relation to the journal of the same name.
It looks like they're coding a new Wiki engine ... very interesting. I keep meaning to write my own Wiki, but I don't care about it enough for it to beat the other demands on my time, and the UseMod Wiki code is just so easy to set up and use that I don't have the need for anything else.
That said, there is plenty of room for improvement in the Wiki world, and Wiki software with integrated blogging, time management, task planning, bug/to-do tracking, calendar and generic database (e.g. Access) facilities would be incredibly useful. Something along the lines of Lotus Notes, except easy to use - I'd like one of those.
Update: The Wiki on socialtext.com looks very UseMod-like, although I'm guessing it's not derived from the same code as it doesn't have a RecentChanges page, and I can't think of why anyone would want to remove that.