spam. My idea is to find a way to tweak (or apply an
existing patch
to) mailman so that messages marked as spam get discarded
automatically
mailman on my mailserver (Ubuntu Dapper out of the box) has this option:
Privacy options...
[Spam filters]
Header filters
Filter rules to match against the headers of a message.
In my case, I use the following:
regex: Subject:.*\{Spam\?\}
Action: reject