[ARC5] Mail List "Spam" Filter- Need Guidance.

[David Stinson]

Can someone point me to a document that outlines
how these blasted mail-list "spam" filters work?
Several times I've had posts blocked and, since I never 
get a "blocked because" message, I can't tell what innocent
word or phrase set the darned thing off.  I once wasted hours
trying to re-write something before discovering the problem.
I know we need a spam filter, and replying to spam 
gets you more spam.  But I need some clues at least, please.
Isn't there a "safe senders' list option??