It's strange that in his list of possible solutions to keep e-mail spam free, there is zero mentioning of hashcash [1].
No, that is not a shitty crypto coin. It's just a computational proof that your computer spend some seconds on hashing, which is fine if you send 1-to-1 emails like real people do, but not if you are a spammer who bought a file with 6 million leaked e-mail addresses.
See Back's 2002 paper "Hashcash - A Denial of Service Counter-Measure".[2]
No, that is not a shitty crypto coin. It's just a computational proof that your computer spend some seconds on hashing, which is fine if you send 1-to-1 emails like real people do, but not if you are a spammer who bought a file with 6 million leaked e-mail addresses.
See Back's 2002 paper "Hashcash - A Denial of Service Counter-Measure".[2]