My incoming spam is running at over 200 junk emails a day, but SpamBayes is catching them all, with virtually no false positives. Bayesian filtering, invented by Paul Graham and available in many open source implementations, is the best answer yet.

About the author.

In 2000 I co-founded Fog Creek Software, where we created lots of cool things like the FogBugz bug tracker, Trello, and Glitch. I also worked with Jeff Atwood to create Stack Overflow and served as CEO of Stack Overflow from 2010-2019. Today I serve as the chairman of the board for Stack Overflow, Glitch, and HASH.