There's a major controversy on a mailing list I'm subscribed to. The list in question (about classic computers) had to change hosts and the software used to manage the list changed.
The upshot is that under the old software, the Reply-To: field was set to be the list itself. That meant that if you wanted to send a private reply, you had to change the address the message was being sent to. As a consequence, a few private messages were sent to the list by mistake.
The new software does not set the Reply-To: field. So to reply to the list, you have to ether change the address the message was being sent to, or do a group reply, which sends a copy to the list as well as to the original sender.
A subtle change, but one that has thrown the list in a tizzy. Some people (like me) like the old behavior. Some like the new behavior (and are telling the ones that like the old behavior to deal or upgrade—odd considering that most accessing the list are using computers deemed too old to use by the rest of society).
The new change was justified by the essay “Reply-To” Munging Considered Harmful by Chip Rosenthal (I think Chip is sore because he accidentally sent private mail to a public list by mistake). But then Simon Hill, in his Reply-To Considered Useful notes that RFC-822 allows munging of the Reply-To: field:
4.4.3. REPLY-TO / RESENT-REPLY-TO This field provides a general mechanism for indicating any mailbox(es) to which responses are to be sent. Three typical uses for this feature can be distinguished. In the first case, the author(s) may not have regular machine-based mail- boxes and therefore wish(es) to indicate an alternate machine address. In the second case, an author may wish additional persons to be made aware of, or responsible for, replies. A somewhat different use may be of some help to "text message teleconferencing" groups equipped with automatic distribution services: include the address of that service in the "Reply- To" field of all messages submitted to the teleconference; then participants can "reply" to conference submissions to guarantee the correct distribution of any submission of their own.
(emphasis added). So. There it is.
But that still hasn't settled the list. Sigh.