Zero-knowledge proofs allow unique consumable tokens that don't reveal the individual who holds them. I believe Ecosia already uses this approach (though I can't speak to its cryptographic security).

That, to me, seems like it could be the foundation of a new web. Something like:

* User-agent sends request for such-and-such a URL.

* Server says "okay, that'll be 5 tokens for our computational resources please".

* User decides, either automatically or not, whether to pay the 5 tokens. If they do, they submit a request with the tokens attached.

* Server responds.

People have been trying to get this sort of thing to work for years, but there's never been an incentive to make such a fundamental change to the way the internet operates. Maybe we're approaching the point where there is one.