I'd appreciate if those who have strong opinions on this would take a look at the analysis below and tell me if I'm missing something. If not, maybe I'll write up a BCP (non-standards-track RFC[1]) so it's on record.
This proposal actually has a history going back to about 2005. I didn't do anything about it because I got a lot of pushback from MUA writers, and writing RFCs is worse than writing PEPs (Pythonistas are either sane or go away soon, not so for IETF mailing lists ;-). But if its still an issue maybe it's worth the effort.
Grant Taylor via Mailman-Users writes:
What I find interesting is that mail.override_list_reply_to is set to True by default in my copy of Thunderbird, 52.5.0.
I think there's an obvious algorithm for "smart single reply":
- If there is a Reply-To, address the message to Reply-To.
- Else if there is a List-Post, address the message to List-Post.
- Else address the message to From. (If there's no From, the message violates the most basic RFCs so all bets are off.)
Assuming that no lists munge Reply-To, I think you'll agree that this is what you want 90% of the time (conservative estimate). There are some issues with this algorithm in practice:
- Some lists should not encourage reply-to-list (eg, for privacy reasons). This can be worked around by omitting List-Post, or solved by additional protocol so that the list sets a header field saying "don't automatically reply here just because there's a List-Post. Given how conservative MUA writers are, I'd say "KISS" for these, and make users cut-n-paste. Most of the time a reply-to-list here is probably thread hijacking anyway.
- Some users will want to override the algorithm and reply specifically to list or author. MUAs should provide buttons or menu items for these infrequently used options.
- Your favorite list munges Reply-To. Nothing changes here, people are still going to be embarrassed by sending remarks intended to be private to a broad audience, and in some configurations of Mailman the original Reply-To or the From will get dupes. At least you can override with a reply-to-author function.
I don't understand what Thunderbird thought they were doing. <shrug/>
Steve
Footnotes: [1] MUA UI best practices like this technically don't have anything to do with Internet protocol semantics.