"...an open source software application designed to significantly reduce the amount of spam (Internet junk-mail) you receive." whitelists, blacklists, challenge/response, tagged addresses, ...
DSPAM is a scalable and open-source content-based spam filter designed for multi-user enterprise systems. On a properly configured system, many users experience results between 99.5% - 99.95%, or one error for every 200 to 2000 messages. DSPAM supports ma