Bruce Lilly writes:
Some people use multiple UAs, possibly at multiple locations. Anything
that requires extensive configuration is a problem.
Even without Mail-Followup-To, having to manually configure several MUAs
is a pain for the user. These users need configuration-sharing tools.
Any good configuration-sharing tool will also handle Mail-Followup-To.
Also, some people read lists via a web archive; an MUA has no way to
determine that.
If the user wants to set Mail-Followup-To for a list, he tells the MUA
about that list. End of problem.
Yes, there are many situations where the MUA can reasonably do this by
default, saving even more time, but we're talking about a trivial amount
of user effort either way. This is once per list, not once per message!
And people change mailing list subscriptions (e.g. when they go on
vacation).
Someone who doesn't really monitor the list probably isn't setting
Mail-Followup-To in the first place. Anyway, what's your point?
---D. J. Bernstein, Associate Professor, Department of Mathematics,
Statistics, and Computer Science, University of Illinois at Chicago