For the past few hours I've been using Cloudmark's new P2P based spam filter plug-in for Outlook and so far so good. In addition to my own simple home grown server-based phrase matching spam filter, I've only had one bogus message reach my inbox. If I factor out what my own spam filter nabbed, that's roughly 1 spam out of 5. Not bad. However, given the P2P roots of Coundmark's spam filter, I can only imagine that it'll get better and better as more people use the system. So, start using it!