Betanews.com reports on it here. No Bayesian filters, no blacklist/whilelist server, no training the service, (right now) it’s just a simple list of block and allow rules that YOU add. Still, if someone on your block list tries to send email, it never leaves their server — they’re informed that they’ve been blocked (or something like that … I’ll have to test it and see). If that’s the case, I kinda like that approach. Rule maintenance could be a pain, though. It’s a new service and there are quite a few rough edges (I’ve sent them 4 comments in the first 5 minutes of my having an account). Try sending me email : ts-test — at — mailami –dot– com.
Service is free for individuals even though it appears that you have to pay something after a 7 day evaluation period.