Re: Understanding response protocols

> I believe it is an "opinion" of whether it is a "propagating a bad 
> practice" to the user.
Yes it is an opinion.  More specifically, it is an opinion that is 
informed by the experience of many people in a variety of situations 
who each have several years' experience in email and mailing lists.  It 
is something that was not obvious when rfc822 was written but which 
came to be realized over time.  It shouldn't surprise anyone that after 
using email for 25 years or so, we learned a few things.
In a nutshell, the reason that having lists set Reply-To is bad is that 
it masks the intent of the original author.  If you receive a message 
from a list with a Reply-To field, did the author set Reply-To, or did 
the list do so?  The recipient's decision about whether to honor that 
field could quite reasonably hinge on the difference.
Lists set Reply-To in part because there was a time when many MUAs 
didn't have the notion of "reply all".  (for that matter, some lists 
used to set From or another return address because many of the MUAs in 
the environments served by those lists - BITNET/RSCS and UUCP - didn't 
really use RFC822 headers).  So in some sense setting Reply-To is an 
anachronism that was inherited from obsolete systems.
I'd be in favor of giving lists a way to indicate their preference 
separately from the author's preference (say, List-Reply-To) -- 
_provided_ that it specified that MUAs don't accept it automatically 
but instead make it easy for the replier to know about the list's 
preference and to choose to use it or not.   (and no, this isn't the 
same as List-Post because a list's policy might be that replies go to 
the author only, or to some other set of addresses).
Keith

p.s. regarding your arguments and experience:  You have given us no new 
reasons for using Reply-To in this way, you have merely repeated things 
we have already heard.  You like to cite your own experience, but many 
of us have comparable experience in terms of years working with email 
in general, and more experience with Internet email.  Most of the 
regular participants of this list have known each other for several 
years and have learned to respect each others' opinions (we've also 
learned where our differences lie).  I get the impression that most of 
us have never heard of you until recently.  Which doesn't mean that 
you're wrong, but it does mean that neither citing your experience nor 
rehashing old arguments is going to convince us that you're right.