I've thought about this as well. I wanted to create anonymity pools and then use zero knowledge proofs to justify predicates about the entire pool. So it would

I've thought about this as well. I wanted to create anonymity pools and then use zero knowledge proofs to justify predicates about the entire pool. So it would be like: 1000 participants formed 10 pools, assigned by random numbers generator. Preficatefoo was true of 19% of pool foo, 24% of pool bar... Participants could then attest: yes, I was in pool foo. But there wouldn't be enough data to reidentify them individually.