Proof of <insert here> seems to be a growing concept. I just wrote and erased a post because half way through I decided to go down a rabbit hole. Long story short it seems like Privacy-Preserving Reputation Systems is a thing. Maybe tech savvy sites like HN could start pioneering using them to drive adoption more widely? This is sort of like encrypted email and other tech areas. It takes adopters pushing things to get the general public to use them. If sites like HN agreed to make them available could that start a real trend?