I've been amongst the beta testers on mollom (I'm uid #8!) for a long time now, here on this blog and with some other projects. I have to say, it's impressive. It's sort of like Akismet but has some interesting goals that are slightly different. The key is in calling it "content monitoring" rather than just "spam blocking" (which it already does effectively). Think: high powered moderation tools - with network intelligence.
Congrats, Dries, on another one! (When do you sleep?!)