Who runs Ethereum?

Ethereum is not controlled by any particular entity. It exists whenever there are connected computers running software following the Ethereum protocol and adding to the Ethereum blockchain. Each of these computers is known as a node. Nodes can be run by anyone, although to participate in securing the network you have to stake ETH (Ethereum’s native token). Anyone with 32 ETH can do this without needing permission.

Even the Ethereum source code is not produced by a single entity. Anyone can suggest changes to the protocol and discuss upgrades. There are several implementations of the Ethereum protocol that are produced by independent organizations in several programming languages, and they are usually built in the open and encourage community contributions.