Using SpamAssassin and friends seems to have
chopped the amount of SPAM I see somewhat. Still a lot of
it gets through anyway. The spammers just get more and more
clever sliding the stuff past the filters.
I've even given some thought to how I could write an
accounting script to calculate the amount of CPU time that
is spent by my mail server processing it and billing the
spammers for their share of what it costs to filter the
crap out. When they refuse to pay take them to small claims
court (keep the $$ amount below US$5000) and sue them.
If they still don't pay take a lien out on their assets
starting with any computers they use to send the stuff.
Probably wouldn't work out in real life but hey... it's
a thought....