Mail.app Junk Mail Filter
Posted in daily
O'Reilly's part two gives interesting information on what Junk Mail Filter is, and isn't. A good read for anyone using Mail.app
The Fight Against Spam, Part 2
Interestingly enough, the technology that underlies the Junk Mail filter began its life as an information retrieval system, developed in the Apple labs to help users who managed thousands or millions of large documents find the one they were looking for easily. In order to do that, this technology had to allow users to perform a search by topic.