Elon Musk：What should be developed on Ethereum?
My top picks
* A globally accessible financial system, including payments, store of value, also more advanced stuff like insurance http://hurricaneguard.io/
* Identity: "sign in with Facebook" -> "sign in with an ethereum account, no intermediaries". Also web of trust...
* All sorts of registries should publish on chain for security and easy verifiability, see my thread on this https://twitter.com/vitalikbuterin/status/1072158957999771648 …
* Experimenting with new forms of human organizational structure, eg. @MolochDAO
* All sorts of micropayment use cases via payment channels...
* Markets for personal data for privacy preserving machine learning (you pay me X, I let you homomorphically execute function Y on my data that's been attestated to by Z...)
* Cryptoeconomics for spam prevention in social networks
* Cryptoeconomics / micropayment schemes to reward publishers of good content
* Testing ground for new market designs, eg. frequent batch auctions, combinatorial auctions, automated market makers (eg. http://uniswap.exchange )
* p2p marketplace for internet connections / incentivized mesh networks
* Identity, reputation and credit systems for those that currently have few resources (eg. refugees)
* Decentralized DNS alternatives (eg. http://ens.domains/ )