May work, but that was possibly where Satoshi got his original idea for Bitcoin from. Based on previous work, use the idea of POW to eliminate spam email. It never caught on for spam email. Nor would it because the global warming people would calculate 20KJ to send an email was destroying the planet. I like the zap to reply type nip needs this. All my notes would be like that and I am ok with reply guy paying 21 sats for each reply. #nostr #bitcoinstr #zap