We haven’t setup the “create a topic by email” on this instance right now. The way it works IIRC is that we need to create an email account (anywhere) dedicated to this and configure a pop3 access for Discourse to poll the email account.
Well, inability to post a new message (as opposed to replying to an existing thread) is a severe disadvantage, compared to the current mailing list.
Also, POP3 is a big warning sign to me. Cannot Discourse offer something like llvm-incoming@discoursemail.com for the LLVM group? And if it cannot – then, again, perhaps the benefits of this platform are overrated…?