Just a little note in here from something I said in the forum when I first got ListMail, about another system I had looked at. I was reminded by the post about mass removals from database.
So many (not just with ListMail but in general..!) are banning signups from some ISP's because of non-delivery problems or false spam complaints.
How about an additional check (similar to the check for duplicate signups), against a disallowed ISP/domain list? This would save removing them later. Just a thought. Probably need it's own error message as well.
