Boost Mail.app's junk mail filtering

The other discovery of the day: JunkMatcher

A set of scripts that can be added to Mail.app rules. It uses various effective techniques such as IP-based filtering, and flexible regular expressions to identify junk mails, and comes with a GUI front end which enables you to analyse what's going on and tweak it efficency. You can even report spam to SpamCop.net directly from the log window.

There's a clip on the product's website that shows it in action.