For instance, you could post messages to each list from
a ``you+$TOKEN(_at_)server(_dot_)com'' address (where $TOKEN is some
string depending on the list you are writing to) and then
have your mail filtered based on that token ....
=v= I've tried this. It resulted in spam being sent both
to you@ and you+token@, since the archives of the "+token"
list were harvested. Others simply strip out "+token" from
=v= There's also the issue that some lists won't accept a
"+" in your email address, often because of lazy programming
on the server end or some such abomination as MS Exchange.