Ethereum is a public, open-source, decentralized computing platform and operating system featuring smart contract (scripting) functionality. It supports a modified version of Nakamoto consensus via transaction-based state transitions. Ethereum was proposed in 2013 by Vitalik Buterin, a cryptocurrency researcher and programmer. Development was funded by an online crowdsale that took place between July and August 2014.
The system went live on 30 July 2015, with 11.9 million coins “premined” for the crowdsale. This accounts for approximately 13 percent of the total circulating supply.
The Ethereum mainnet is the original Ethereum blockchain, as opposed to any testnets or private blockchains that may have been created for development or testing purposes. The mainnet is the only Ethereum network where real value can be sent and received, and where smart contracts can be deployed and used in real-world applications.
The Ethereum mainnet is also sometimes referred to as the “Ethereum network” or “Ethereum blockchain”, although technically there is a difference between the two: the Ethereum network refers to the peer-to-peer network of nodes that relay transactions and propagate blocks, while the Ethereum blockchain refers to the actual data structure that stores all of the transactions and state changes that have ever occurred on the network.