[selfsimilar]

Hashcash was a proof-of-work system that would have put a computational tax on email. I don't know what kept it from getting more traction other than simple chicken-and-egg network effects, but it's a good idea, and worth resurrecting.

http://www.hashcash.org

[ramses0]

Email2000 is the only answer: https://cr.yp.to/im2000.html

TLDR: Mail storage is the sender's responsibility. The message isn't copied to the receiver. All the receiver needs is a brief notification that a message is available.

[layla5alive]

Sounds like a horrible system where you retain many of the problems of email (you still need to deliver notifications) and new surveillance and persistence and mutability problems layered on top..