Another anti-spam idea I'm thinking about using: Use more than one email address for newsgroup posts. Identical mail arriving at both addresses is "harvested" and tosses as spam.

Combining that with a spider catcher idea, you could have a dummy page with a special email address on it, and anything going there is assumed to be harvested spam, and that can be used as a template for what to filter out of other mailboxes.

—John