I don't concern myself with who is reading messages and "participating".
However, once a year I ask members to "opt-in" to stay on the list. This might?be difficult for those with large memberships.
My group is small so the member count floats between 70 and 100.? If someone "opts-in", I know that they are interested
in staying on the list. I'm ok with lurkers.
Maclean Kirkwood