How to actually combat spam
Make it illegal for VISA/Mastercard/etc. to process spamvertised products. The U.S. government just did this with Internet gambling, and the credit card companies promptly stopped handling such transactions for U.S. accounts.
It'd be easy for VISA to cut a large enough chunk out of the business so as to make it unprofitable. All they do is set up a few honeypot email addresses. Then take a fake credit card to all the spamvertised products and see which processors and businesses are handling the product. Then cut them off and reverse their last month's worth of charges automatically.
Sure, there'll still be a lot of spam related to stock pump and dumps, Nigerian scams, and whatnot, that don't depend on credit cards to work. But a ton of it now becomes unprofitable for spammers with the risk their charges get auto-reversed if they are discovered.
It'd be easy for VISA to cut a large enough chunk out of the business so as to make it unprofitable. All they do is set up a few honeypot email addresses. Then take a fake credit card to all the spamvertised products and see which processors and businesses are handling the product. Then cut them off and reverse their last month's worth of charges automatically.
Sure, there'll still be a lot of spam related to stock pump and dumps, Nigerian scams, and whatnot, that don't depend on credit cards to work. But a ton of it now becomes unprofitable for spammers with the risk their charges get auto-reversed if they are discovered.