LISTSERV already has in place the vehicle you need. The list
owner can set the Ack keyword to either Yes, No, or Msg, and
indivuals on the list can set their preference by TELLing
LISTSERV to SET ACK YES or NO or MSG. "Yes" requests full
acknowledgements, and is the default. "No" currently sends one
interactive message saying "Your mail for ... has been
successfully processed.", but it has been suggested that even
that is too much. "Msg" causes the stats to be sent via
interactive messages instead of as a mail file.
The only thing missing is a way to set the Ack value for
senders who are not also receivers (although changing the list's
value would probably do the trick at the expense of those who
haven't made up their minds.)
Ross