Ethereum is a blockchain platform, allowing users to create decentralized applications (dApps) based on smart contracts.
A smart contract is a set of rules between two or more parties.
All computing devices participating in the ethereum network present a distributed virtual machine. This virtual machine checks conditions under which smart contracts should be fulfilled, and then executes an action, pre-defined in smart contracts.
The ethereum blockchain made it possible to implement thousands of applications within a single platform, without the need to create a new blockchain for each application.
Ethereum's main ideologist is Vitalik Buterin, a Canadian developer with Russian roots. He was drawn to cryptocurrencies back in 2011, when he founded the Bitcoin Magazine, and wrote numerous articles on cryptography and blockchain.
In 2013 Buterin decided to launch an open decentralized platform that is superior in functionality to bitcoin blockchain. He published a white paper, describing in detail the platform's algorithm for creating dApps. He was the first to launch an ICO to raise funds for his crypto project, collecting more than $18 million in BTC.
In the ethereum blockchain miners earn ether (ETH), a cryptocurrency that fuels the network. Ether is used by application developers to pay for transaction fees and services on the ethereum network. Ether is also tradable on crypto exchanges as any other cryptocurrency.