This is exactly the same problem faced by hashcash, just wrapped up in more layers of complication. If emails require a $1 attachment to get into your inbox, you will receive no emails, since nobody is currently sending any emails with $1 attached. Just rewrite my above comment, but replace "hashcash" with "dollars".
> I assume the money transfer can be solved today using Bitcoin, and it wouldn't be a terribly complicated protocol.
You do realise that Bitcoin itself is a complicated protocol built on top of hashcash, right? Keypairs, blockchains, mining, etc. is just adding unnecessary complexity to this problem; not to mention your choice of the US dollar as the denomination, which requires an exchange rate, etc.
Hashcash is pure waste, this at least benefits the one whose attention is wasted by the spam.
> You do realise that Bitcoin itself is a complicated protocol built on top of hashcash, right?
Of course, but it already exists.
> If emails require a $1 attachment to get into your inbox, you will receive no emails, since nobody is currently sending any emails with $1 attached.
Yes, but assume there are people sending bulk email legitimately who have delivery issues. All you need is one major provider to accept it and then there is a benefit for senders. DKIM and SPF prove that the deployment problem can be overcome, even for relatively weak attacks on the spam problem.
This is exactly the same problem faced by hashcash, just wrapped up in more layers of complication. If emails require a $1 attachment to get into your inbox, you will receive no emails, since nobody is currently sending any emails with $1 attached. Just rewrite my above comment, but replace "hashcash" with "dollars".
> I assume the money transfer can be solved today using Bitcoin, and it wouldn't be a terribly complicated protocol.
You do realise that Bitcoin itself is a complicated protocol built on top of hashcash, right? Keypairs, blockchains, mining, etc. is just adding unnecessary complexity to this problem; not to mention your choice of the US dollar as the denomination, which requires an exchange rate, etc.