Ethereum is a decentralized, open-source blockchain platform that was proposed by Vitalik Buterin and developed along with Gavin Wood and went live in July 2015. Unlike Bitcoin, Ethereum's primary focus is enabling smart contracts and decentralized applications (dApps) to be built and run without the need for intermediaries. Ethereum's native cryptocurrency, Ether (ETH), is used to power these applications and pay for transaction fees on the network.