Yesterday I installed the new 2.0 version of Spamfire on my main Mac. I've been using Spamfire for almost exactly two years. The old version used regularly downloaded rule-based filters to turn away the junk, and worked reasonably well for awhile. The new version adds trainable, Bayesian filtering as well, and is working quite a bit better. (Be careful when installing it, by the way: it would not work for me when I put the application in a folder called "Spamfire ƒ" with a curly f—but it runs great if installed directly into the Mac OS X Applications folder.)
Here's why I need the upgrade. A good chunk of my e-mail has spam filters applied before I even see it, from either my hosting provider, my e-mail forwarder, my ISP, or a combination of two or three of those. I never see hundreds or thousands of of my daily spam messages. Even so, yesterday Spamfire intercepted more than 900 spam messages. Overnight, it caught 244 more, letting through 5 legitimate e-mails. Yes, five.
And I use Macs, so I'm not even worried much about spyware and other crap. If I were getting this sort of onslaught on a Windows box, I might just just revert to paper and typewriters. Or maybe CB radio.