Many person-lifetimes of work have been spent on fighting spam/abuse/harassment on internet platforms. The idea proposed here is to greatly reduce this cost by making users pay a small, fully refundable deposit.

Interesting. I wrote about this some time back[0]

The problem with money how ever is that not everyone can afford to pay a bond.

My suggestion was to use pow.

[0]: https://as1ndu.xyz/2019/11/proof-of-work-on-layer-two/

Hey, cool!