indimail-spamfilter is a very minor adaptation of bogofilter to work seamlessly with indimail-mta

Bogofilter is a fast Bayesian spam filter along the lines suggested by Paul Graham in his article "A Plan For Spam":
http://www.paulgraham.com/spam.html

with algorithmic changes suggested by Gary Robinson in:
http://radio.weblogs.com/0101454/stories/2002/09/16/spamDetection.html

and in "A Statistical Approach to the Spam Problem":
http://www.linuxjournal.com/article.php?sid=6467

This version improves on the papers by doing smarter lexical analysis.
In particular, hostames and IP addresses are retained as recognition features rather than broken up. Various kinds of MTA cruft such as dates and message-IDs are discarded so as not to bloat the word lists.