Vitalik Buterin, co-founder of ethereum, today published the article "What do I think about biometric proof of personhood?" to express his views on biometric proof of personhood. He says that, in principle, the concept of proof of personhood seems very valuable, and that while various implementations have their risks, so does the absence of any proof of personhood at all: a world without proof of personhood seems more likely to be a world dominated by centralized identity solutions, money, small closed communities, or some combination of the three.