[Spambayes] Deployment Guido> Takers?  How is ESR's bogofilter packaged?  SpamAssassin?  The
    Guido> Perl Bayes filter advertised on slashdot?

Dunno about the other tools, but SpamAssassin is a breeze to incorporate
into a procmail environment.  Lots of people use it in many other ways.  For
performance reasons, many people run a spamd process and then invoke a small
C program called spamc which shoots the message over to spamd and passes the
result back out.  I think spambayes in incremental mode is probably fast
enough to not require such tricks (though I would consider changing the
pickle to an anydbm file).

Basic procmail usage goes something like this:

    :0fw
    | spamassassin -P

    :0
    * ^X-Spam-Status: Yes
    $SPAM

Which just says, "Run spamassassin -P reinjecting its output into the
processing stream.  If the resulting mail has a header which begins
"X-Spam-Status: Yes", toss it into the folder indicated by the variable
$SPAM.

SpamAssassin also adds other headers as well, which give you more detail
about how its tests fared.  I'd like to see spambayes operate in at least
this way: do its thing then return a message to stdout with a modified set
of headers which further processing downstream can key on.

Skip