K9 forum?

[Aaron]

By definition, a Bayesian filter bases its' decision as to
whether or not a message is spam from reading the content of the
message.

Small nitpick. Technically not true. Through Bayesian filtering has
traditonally being used with full headers and bodies, there is no reason
why they can't be done only on headers.

I have read about experiments by the spambayes people who used bayesian
filtering with headers with some (90%) succuess.

Aaron (my email is not munged!)