Approaches range from biometric (World's iris-scanning Orb) to aggregate signals: Human Passport (formerly Gitcoin Passport, acquired by Holonym's human.tech in late 2024) lets users collect verifiable "stamps" from web2 and web3 accounts into a Unique Humanity Score that apps can gate on — proving humanity without exposing identity.
In the agent economy the point isn't to exclude agents — it's to bind them to humans. An agent acting for a verified person (with a mandate or an agent wallet) is a customer; a swarm of agents pretending to be thousands of people is a Sybil attack. Proof of personhood is the anchor that keeps one human behind each delegated identity.
No — it distinguishes them. A delegated agent can act under a verified human's identity and authorization; what proof of personhood blocks is one operator masquerading as many humans (Sybil attacks) in votes, airdrops and reward programs.