Re: Generating Mail-Followup-To: headers

[Per Abrahamsen <abraham@dina.kvl.dk>]

I think Paul Jarc is right:

1. Ignore folders.  
2. No magic headers.
3. A single variable:

(defcustom message-subscribed-lists nil
   "A list of regexps matching mailing list you are subscribed to.

Automatically set the Mail-Followup-To header to the combined content
of the To and CC headers when sending a mail message where an adress
in the To or CC header matches one or more of the entries in this
list.

The effect is that you won't recieve private copies of answers to the
message from users of mail clients that implements the
Mail-Followup-To header."
  :type '(repeat (regexp :tag "List address"))
  :group 'message)

The Mail-Followup-To header is inserted only after the user have
called message-send.

I'd have prefered to do something smart with folders, since I use
folders for everything.  But given the intented content of MFT (= To + Cc),
I don't think that would be robust.

A side advantage of this is that it can be implemented entirely in
Message, with no Gnus knowledge.