Eigenpoll : Spam fighting software : DSPAM

ttp://www.nuclearelephant.com/projects/dspam/

DSPAM (as in De-Spam) is an extremely scalable, open-source statistical-algorithmic hybrid anti-spam filter. A majority of users running v2.10+ achieve filtering rates ranging from 99.92% - 99.98+%, DSPAM is currently effective as both a server-side agent for UNIX email servers and a developer's library for mail clients, other anti-spam tools, and similar projects requiring drop-in spam filtering. DSPAM has been implemented on many large and small scale systems with the largest systems being reported at about 125,000 mailboxes.