I like this and would pay for such a system. It doesn’t need to use blockchain though, a normal escrow system would work. Everyone who signs up puts a dollar in

I like this and would pay for such a system. It doesn’t need to use blockchain though, a normal escrow system would work. Everyone who signs up puts a dollar in escrow. If you send an email to your contact it’s free. If you send outside your contacts it costs a penny, but the recipient can return the penny to you if they want. This makes it prohibitively expensive to send low value email, free to send high value email, and slightly expensive to send “probably valuable” email.