I have encountered many "unmonifored" yahoo groups...where either the monitor's e-mail addy is invalid ....

Question

Continuing...e-mail address of group monitor is either invalid or mailbox is full and none are allowed in.

Answer 1

I encounter them all the time. I just ignore them.

Answer 2

there's zillions of groups like that. nothing you can do about it. locate a group with an active owner

it is up to each member to stay or leave a group that has no active owners, but there's nothing that can be done if there is no active owner.