[sf-lug] email, Reply-to:, lists, and all that jazz

Rick Moen rick at linuxmafia.com
Tue Apr 29 10:54:04 PDT 2008

Quoting Asheesh Laroia (asheesh at asheesh.org):

> P.S. On a list without reply-to munging, the CC: line becomes enormous 
> when everyone replies-all.  

...but then, FYI, shrinks to nothing again whenever someone using mutt
or Emacs GNUS participates in the thread -- because both those MUAs have
list-handling code to compensate for the cited undesired side-effect of
mailing lists' inability to fully emulate NNTP netnews as people would
actually prefer.

(Example:  This post.  Quod erat demonstrandum:  The removal of non-list
addresses from my draft headers occurred automatically.)

I'm guessing that Alpine doesn't yet have list-reply handling.  You should
file a feature request with UofW.

> I use a procmail+formail filter to remove duplicate inbound messages
> based on their Message IDs - but if no munging + "use Reply to all" is
> the most elegant solution, it's still not very elegant.

No elegant solution is even theoretically possible, because mailing
lists simply lack netnews/NNTP's built-in infrastructure support for
distinguishing between reply (private) and followup (public).  Mailing
lists attempt to emulate many-to-many forum semantics (i.e., netnews)
over a one-to-many transport (i.e., SMTP):  Consequently, you as mailing
list admin get to pick your choice of undesired side-effect.  You either
deliberately sabotage subscribers' ability to do private reply (with
periodic resulting social catastrophes), plus destructive mail loops, on
the one hand, or live with the knowledge that there will be some
generation of so-called "duplicate" mails by less-advanced participating
MUAs, on the other.

If you want full handling of the private / public messaging dichotomy
with no undesired side-effects, go straight to _Usenet_.  Otherwise, a
standards-compliant SMTP mailing list leavened with at least one mutt or
GNUS user is exactly as good as it _can_ get.  ;->

Here's the bog-standard procmail de-duping recipe you speak of (straight
from "man procmailex"):

              :0 Wh: msgid.lock
              | formail -D 8192 msgid.cache

Of course, the "Waaah!  Yes, you've proven that munging technology is bad
and has been utterly rejected by standards authorities, but it's what
we want" people aren't going to _bother_ using procmail, but there's a
nice pool of water for any horses willing to drink.

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