I think the crowd I’m talking about may be even more web adverse than you, Ian. 
This is what I meant:
Ack – Check this box to report on whether or not subscriptions are set to receive an “acknowledgement” message when they post to the list. For example:
Your message dated Thu, 2 May 2002 16:08:28 -0400 with subject “My message” has been successfully distributed to the MYLIST list (123 recipients).
https://www.listserv.net/manuals/16.0/htmlhelp/site%20managers/SubscribersCorner.html#2348127