SpamSlam for Mac

From ilesa:

SpamSlam is a effective spam-eliminating tool compatible with all e-mail clients. Unlike filter based anti-spam tools, SpamSlam downloads all of your mail and uses a whitelist combined with a challenge/response system to dynamically rid your life of annoying junk mail. Only real people respond to the challenge e-mail allowing only legitimite addresses to be whitelisted and only important emails to enter your account. Once a person's e-mail address is in your whitelist he or she can e-mail you freely. New updates add a rules system that allows greater flexibility, including real mailing list support and the ability to blacklist and whitelist entire domains. SpamSlam is a one step process to hassle-free electronic communication. Version 2.1 adds the following: Several critical bugs were fixed. Current SpamSlam users are urged to upgrade at their earliest convenience. SpamSlam's AccuFilter has been rewritten and delivers much improved and nearly perfect classification of junk messages.