Thread happening on multiple mailing lists + Discourse


Recently, we’ve been advertising to our users the fact that Discourse can be used via e-mail, not only to reply to an existing topic but also to create a new one. Some users have started experimenting with cross-posting a question to a mailing list and Discourse. The first thing that we’ve noticed is that Discourse won’t “reply all”, i.e. mailing list subscribers or people in cc of the first post won’t receive replies on Discourse itself. This might be something to consider as a possibly future improvement… or not.

But more problematic, a recent thread that was started on 3 mailing list at once + our Discourse got 28 replies in two days where the Discourse e-mail address was kept in the recipients, creating as many new threads on our Discourse forum! I had to manually move every one of these posts to the initial thread and unlist them. New replies keep generating new topics and I’m wondering what to do. The only solution I see for now is temporarily disabling the corresponding e-mail address and documenting that it’s not a good idea to start a thread on a mailing list + Discourse at once.

Any help / advice would be welcome.



That’s just rude.

Back in the day, I’d set up a procmail filter (According to Wikipedia “Note: Procmail is unmaintained (last update 2001),”) that would send stuff with that subject to /dev/null. I’m not sure what I’d do today, but some kind of filter of the mail before it gets ti Discourse is what you need, I’m afraid.

Good luck.

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I’m using a version hosted by Discourse inc. so I don’t think that I can do that kind of filtering…

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Yeah, you’d need to use some other address that you forwarded through a filter and then to your Discourse mailbox. I’m pretty sure that you can use something other than their mailbox if you wanted to, but forwarding to the existing mailbox is probably easier.

The fact that the premier tool to solve your problem hasn’t been updated in 20 years says a lot, I’m afraid. If you ran it through a gmail account you could use its filters and then forward to your existing mailbox. I’d think that you already have some such forwarding in place if you’re getting mail delivered to a category.

I used to make decent money managing mailing lists. I think they’re pretty much a bad idea held on to only by old people not unlike me.

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Actually, Discourse supports providing one e-mail address per category, so no need for any additional setup.


When you enable “Category mirrors a mailing list”, replies to the email thread will end up in the same topic. See Start a New Topic via Email ✉.

It would be very interesting if Discourse could perform a reply all when new messages are posted on the topic though! This would provide a two-way mailing list interface.


Thanks! It looks exactly like what I was looking for. I hadn’t enabled the setting so far simply because I didn’t know what it meant.