Mailing lists avoid sending duplicate copies of emails

[William Grant]

Launchpad's mailing lists do not forward emails to people if they are already directly in the To line. This is a bad idea, so stop it.

[Barry Warsaw (barry)]

I'm not so sure. Lots of people want the duplicate reduction this provides, but there is a price to pay because the explicitly named recipient will only get the direct copy, not the list copy.

This is a standard Mailman feature. I think the default works for most people, but there are (I'll say "advanced") users who know how to handle the duplicates perfectly well and prefer to get the list copy. We should allow the user to chose which option they want, but I think the default is correct.

[Max Kanat-Alexander (mkanat)]

This is a standard mailman feature, but it is not a standard mailman default. At least, it hasn't been the default on any of the systems that I use. The problem is that you get a message without List-Id headers, so (a) it doesn't filter properly and (b) your email client can't figure out that it should "reply list" instead of "reply all". Ultimately, this ends up encouraging off-list communication, because hitting the "reply" button goes to the sender, when they've CCed you (which they always do, because they use Reply All instead of Reply List, because of this bug).

[Robert Collins (lifeless)]

Another approach would be to deliver only the list copy. That of course has its own issues.

However, most of our users use gmail, and gmail does de-duping itself on message id, so most of our users will a) not notice if we change the setting, and b) not care either.