That’s why I specified a proof-of-stake cryptocurrency. They use so much less energy that it is practically negligible in comparison, and more on the order of traditional online transactions.

Yeah, exactly. A regular user isn’t going to notice an extra few cents on their electricity bill (boiling water costs more), but a data centre certainly will when you scale up.

Scarcity is what powers this type of challenge: you have to prove you spent a certain amount of electricity in exchange for access to the site, and because electricity isn’t free, this imposes a dollar cost on bots.

You could skip the detour through hashes/electricity and do something with a proof-of-stake cryptocurrency, and just pay for access. The site owner actually gets compensated instead of burning dead dinosaurs.

Obviously there are practical roadblocks to this today that a JavaScript proof-of-work challenge doesn’t face, but longer term…