My husband runs two mailing lists from our ISP. One of them was recently subscribed to a rare poultry mailing list. Yeah, the LIST was subscribed to another list. See, the list address is very normal. It doesn't appear to be a list address if you just read it. So somebody, and we have no idea who, subscribed that normal-looking address to a mailing list with over 1000 subscribers.
The results have been messy. Because my husband's list is closed, only subscribers can post to it. So if a message comes in from someone who isn't a subscriber, the list software kicks back a note saying "you aren't subscribed to the list" and so on.
Well, on my husband's side, he suddenly started receiving 40 or so messages a day about chickens, and with every message he got a copy of the note saying "You aren't subscribed". So he tried to get off the Chicken List, but his mailing list address is a mailing list address: he can't send notes from it! So he can't automatically unsubscribe.
On the Chicken List side, every single note they sent is returned to their list by my husband's list with that same note, which they didn't read or couldn't understand, because they thought it was a virus or something.
So the Chicken lovers are angry at my husband and my husband is angry at the Chicken List owner for not removing the address when he asked.
So I finally got interested in the fray, and found the Chicken List on Yahoo Groups, subscribed to it, and sent a note to them explaining the situation. I then contacted Yahoo support and asked that my husband's list address be taken off the Chicken List. Then I did a little research, and discovered that the Chicken List has a parallel list that was created two years ago when the original list owner got very ill and couldn't take care of the list. So there is apparently NO list owner that can remove my husband's mailing list address from the list.
Which just goes to show that a Chicken List with its head cut off is a menace to the 'net.