>My MacOSX Mail application cannot sort mail from here into the right  
>postboxes.
Then you must not be doing it right.  Any message coming
through the list has in the headers:
  Sender: owner-info-cyrus@list...

I haven't had a problem with sorting on that with any tool that I
have tried.

While I see how some people may want to have some special identifier
in the Subject of the message, I think the claims that they can't get
things auto-sorted are exagerations.   More often it's the case
they don't want to auto-sort, but be able to quickly pick things out
of their unsorted incoming message list.

Getting the Subject line tags right can be a problem too.  Some clients
mess up various replies so you get things like
Re: [info-cyrus] RE: [info-cyrus] FWD:Re: [info-cyrus] put on the subject line.

-_Gene
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