What about a program like:

http://freshmeat.net/projects/dcc-source/

I haven't looked into it, but it looks like a way to help filter the mail by
comparing checksums of messages with a repository.  Then you aren't blacklisting
whole email systems, just the spam itself.

> Use a spam clearinghouse to report spam and get the IP blocks into an RBL service.
> 
> If you use postfix as your MTA you can use the lines below to stop a LOT of spam.
> With the combined config below and regexp matching I stop 99.999% of incoming
> spam to all domains I handle. Whatever gets thru is added to "header_checks".
> 
> WARNING: There are a LOT of misconfigured email systems out there and
>          you will stop a lot of legitimate mail from clue deprived admins.
>          The good news is they will get a 4xx error and if you check your
>          logs, you can whitelist the mail servers you want mail from.
>          Make sure you understand what the lines below will do before even
>          attempting to apply this ruleset to postfix.
>          I have left out "header_checks" and "body_checks" since you will
>          want to set them up yourself and I have over 559 regexp entries
>          that are pretty harsh like rejecting email from "com.ar"
> 
> NOTE: Order of the checks is important, keep that in mind.
> 
> maps_rbl_domains = relays.ordb.org,
>  relays.visi.com,
>  inputs.orbz.org
> 
> smtpd_recipient_restrictions = permit_mynetworks,
>  reject_unauth_destination,
>  reject_maps_rbl,
>  reject_invalid_hostname,
>  reject_unknown_hostname,
>  reject_unknown_sender_domain,
>  reject_unknown_client,
>  reject_non_fqdn_sender,
>  reject_unauth_pipelining,
>  reject_non_fqdn_hostname,
>  permit
> 
> 
> On Sun, Mar 17, 2002 at 02:00:46AM -0800, mike wrote:
> >
> > Quick question.  I hate spam like the rest of us.  I
> > am just thinking out loud, and would like feedback.
> > What if I set up a web site giving e-mail address, and
> > offensives of people doing this spamming, and post it
> > on the web and asked people to e-mail these
> > offensivers?  Do you think that might help at all?  I
> > am thinking if the billing, tech support, and admin
> > contacts receive several contacts a day on the same
> > issue, then maybe they will take notice.  Then there
> > is the legal sitution that I might be held
> > responsivable for.  If anyone has any thought on this
> > idea let me know.  I am sick of spam!   I am sorry for
> > the spelling.
> >
> >                                    mike
> >
> > __________________________________________________
> --
> Jean Francois - JLF Sends...                                               /"\
> "Tell them we are not Gods, but SysAdmins, which is the next best thing."  \ / ASCII Ribbon Campaign
> Getting Facts - $35: http://www.winface.com/blurb.html                      X  Against HTML Mail
> Getting Certs - $40: http://www.brainbench.com/transcript.jsp?pid=1214021  / \
> Getting Published - Priceless: http://www.informit.com/authors/index.asp?authorid={6AD44647-E752-4CAB-B911-D3246F294DBA}
> 
> ________________________________________________
> See http://PLUG.phoenix.az.us/navigator-mail.shtml if your mail doesn't post to the list quickly and you use Netscape to write mail.
> 
> PLUG-discuss mailing list  -  PLUG-discuss@lists.plug.phoenix.az.us
> http://lists.PLUG.phoenix.az.us/mailman/listinfo/plug-discuss