Long ago I put ietf-822(_at_)imc(_dot_)org into my ~/.lists configuration file.
Here's what that told my MUA: ``Please _automatically_ request that my
address be excluded from followups to any message that I send to
ietf-822(_at_)imc(_dot_)org(_dot_)''
(The MUA communicates the request using Mail-Followup-To. In detail: if
one of my outgoing messages has ietf-822(_at_)imc(_dot_)org in To or Cc, the MUA
automatically copies To+Cc to Mail-Followup-To---unless there's already
a Mail-Followup-To, of course.)
I commented that old message injectors don't have this feature, so they
have to be changed. MUAs need a few extra lines of code. This fact isn't
tied to the protocol for communicating the request; the MUAs simply
don't have the code to inspect and copy To+Cc.
(The feature _is_ supported for all shell users on qmail boxes, for Mutt
users, and for Gnus users---in every case, using Mail-Followup-To.)
A few people have now sent messages claiming that old MUAs _do_ have
this feature---but they're talking about a _different_ feature, one that
fails to accomplish the same result. Specifically, many MUAs can inspect
the _mailbox_---which is quite different from inspecting To+Cc---and add
a preconfigured field---which is quite different from copying To+Cc. The
overall result is a remarkably poor approximation to what users want.
The bottom line is that the MUAs still need to be changed.
---D. J. Bernstein, Associate Professor, Department of Mathematics,
Statistics, and Computer Science, University of Illinois at Chicago