<p>SpamSieve lets you add superior Bayesian spam filtering to Mac OS X email clients, is just as easy to use as Mail&#39;s junk mail filters, and can give you statistics, too.</p><p>SpamSweep successfully combines high precision spam filtering with a simple and easy to use interface. It&#39;s a pity processing mail is a tad slow in SpamSweep, and a POP proxy mode would be nice.</p><p>POPFile is a powerful and flexible email classification POP and NNTP proxy that you can use to filter spam efficiently and categorize good mail automatically. Unfortunately, POPFile can grow a bit heavy on memory and CPU load if you have trained on lots of mail.</p><p>Spamfence is an effortless but highly effective spam (and virus) filtering service.<br/>Its only real shortcoming is that Spamfence relies on forwarding and requires two different email accounts.</p><p>Spamfire combines efficient Bayesian filtering and ease of use to form a great anti-spam tool. It could integrate with email clients even better, though, and be a bit snappier overall.</p><p>Spamato filters POP and IMAP accounts for spam with the potential for high precision and plug-ins that make it easy to use in Outlook and Mozilla Thunderbird. Unfortunately, Spamato can be a bit overwhelming with its multitude of options and little help.</p><p>Personal Antispam X5 employs a number of tactics to rid Mac OS X Mail and Entourage of spam — a bit overeagerly, unfortunately.</p>SpamBayes employs sophisticated analysis using Bayesian statistics to rid your email Inbox of junk mail precisely and in an effortless manner.<br/>It would be great if SpamBayes&#39; classifying power could be used to further categorize and prioritize good messages, and plug-ins for programs other than Outlook and Mozilla Thunderbird would be welcome.