You are thinking of approved domains only, and perhaps people can vote them out. But, what you are describing is an RBL (in this case a real time whitelist ins

You are thinking of approved domains only, and perhaps people can vote them out. But, what you are describing is an RBL (in this case a real time whitelist instead). I like the ability for existing members to be able to vote out other members, but you run into the issue of spammers creating a million domains and then being able to vote out all legitimate members.