Comments:

Each mailer of a spam should be held liable for it's contents. If each mailer was required to identify the sent mail as contents contain advertising, we could decide to accept it or not. Put (Contains Advertisement) in the subject line. Any business or person with a person's opted in name and e-mail address would be legal to send to that address unless that person requests to be removed. By remove, means to not place some in other list but removed. Each removal link must work. End US citizens ability to use Foreign isp's or foreign mailboxes to send spam to US citizens. Only allow advertisements to offer a business to an opt-in list built by that company for it's contacts. Absolutely forbid any mail list to be sold by anyone to anyone.