I recently learned that proof of work was actually invented long before Bitcoin to combat spam, but the idea didn't take off, sadly: https://en.wikipedia.org/w

I recently learned that proof of work was actually invented long before Bitcoin to combat spam, but the idea didn't take off, sadly: https://en.wikipedia.org/wiki/Proof_of_work https://en.wikipedia.org/wiki/Proof_of_work https://en.wikipedia.org/wiki/Hashcash https://en.wikipedia.org/wiki/Hashcash https://scottpeterjohnson.github.io/hashwall/dist/index.html https://scottpeterjohnson.github.io/hashwall/dist/index.html