This issue is just for discussion purposes really.
Presently when Moodle sends out forum messages it uses 'email@example.com' for the from header on the first post and then (depending upon settings) the posters email address for replies.
I wonder whether it would be better netiquette if we were to always use noreply for the from header and put the posters email address in the reply-to header.
Forum emails I receive from moodle.org currently don't display the users profile pic or group pics if the email appears to have come from a poster I have not yet trusted... just a hunch but this switch may fix that as well.
Anyway it's been a long time since I'm dealt with email servers/clients so perhaps we have it correct presently, if so ignore this issue!