Comment by locknitpicker

> What if a single email cost $0.001 cent to send, and it was paid to the recipient? For $10, you could send 10,000 emails. For recipients, every 1,000 emails they get is a dollar in their wallet.

I'm not sure you realize your proposal's only contribution is to worsen spam. You are unwittingly creating an incentive for email providers to lift anti-abuse filters and to maximize the volume of spam delivered to you.