The format and timing of messages suggests that it may be managed using a manual process. This is surely too user intensive for a list of this size and something better is desirable. There are much better alternatives available such as listserv and majordomo etc. Plus it provides a model for a self- supporting service via banner advertising etc. There are a lot of enquiries rather like those answered by MUG, and some of the users of sci.math.symbolic seemed to find this irritating.
Different people prefer different formats.
Replies to the Newsgroup would also be sent by mail to those on the maillist and the Mailist replies would also be put on the Newgroup. As I assume both would be moderated this should not involve any significant additional work. This gives Maple a Newsgroup and the corresponding exposure and also retains the advantages of the Maillist. Maple users could choose either or both as suits them.