ZFilter is a vastly superior e-mail filtering program that can (among billions of other things) automatically destroy junk mail, chain letters, mail-bomb attempts and spam from fly-by-night eMail addresses before they even have a chance to contaminate your in-box. ZFilter can be used to direct incoming negative e-mail energy from losers and freaks and turn it against them. ZFilter lets you create form letters to send personalized replies to hordes of unimportant people without wasting more than a few minutes of your ever-so-valuable time to set it up. ZFilter can track and maintain logs of who writes to you the most, what actions it has taken the most, and up-to-the-second reports of how much mail has been received during the current year, month, day, hour, and minute.
As hyped as it sounds, it is really useful. Works well with ELM and PINE, as well as people who use SMTP/POP to get mail (although you can't use "save-to-folder" commands with POP)