If the Sha256 of the email content together with the blob start with Y zeros, then the receiving email client knows the creator of such email INVESTED energy to create the email. Each receiving email client can demand different number of zeros as compute becomes cheaper.
That way, when I send a cold email to someone in which the X-Human-Hash starts with a 1000 zeros is IT CLEAR THAT IT IS A F-ING IMPORTANT EMAIL!! NOT SPAM. This would important for legal teams, engineering teams, etc.
It is the 21st century, I have a SaaS that makes $1.5m per year, I live in a super advanced nation, use best practices, and I CAN'T GUARANTEE an important email INBOXES!? How did we get here.
Thoughts?
If you wanna work on this with me email me at somid3-at-gm@il-D0t-c0m
But, it's very worth thinking about whether there are approaches that don't have this problem. In a way, that question is parallel to the ongoing debate in cryptocurrency mining about whether there's a way to do a mining-based blockchain that will continue to be decentralized and involve regular people's devices somehow, and that won't even up giving an advantage to centralized miners who invest a lot of capital into server farms and custom hardware. I know one recent entrant in this area is Chia which uses a proof-of-storage mechanism; I don't know whether that actually succeeds in reversing economic pressures toward centralization, but it could be interesting to look into whether its structure and incentives could somehow be bootstrapped into a "apparently, someone probably dedicated some moderately expensive resources that are probably on an ordinary PC, for a moderate period of time, in order to send you this message". And again, without ultimately getting hijacked by botnets that can make third parties' PCs participate illicitly. :-(