Ethereum is a decentralized, open-source blockchain with smart contract functionality. Ether (ETH) is the native cryptocurrency of the platform. It is the second-largest cryptocurrency by market capitalization, after Bitcoin. Ethereum is the most actively used blockchain.
Ethereum was proposed in 2013 by programmer Vitalik Buterin. Development was crowdfunded in 2014, and the network went live on 30 July 2015, with an initial supply of 72 million coins. The Ethereum Virtual Machine (EVM) can execute scripts and run decentralized applications. Ethereum is used for decentralized finance, and has been utilized for many initial coin offerings.
In 2016, a hacker exploited a flaw in a third-party project called The DAO and stole $50 million of Ether. As a result, the Ethereum community voted to hard fork the blockchain to reverse the theft and Ethereum Classic (ETC) continued as the original chain.
Ethereum has started implementing a series of upgrades called Ethereum 2.0, which includes a transition to proof of stake and an increase in transaction throughput using sharding.