What is Ethereum?

Ethereum was proposed by Vitalik Buterin in 2013 and launched its mainnet on July 30, 2015. Unlike Bitcoin, Ethereum is programmable: smart contracts written in Solidity execute on the EVM (Ethereum Virtual Machine) and underpin the entire DeFi, NFT, and DAO stack. The Merge (September 2022) migrated Ethereum from Proof-of-Work to Proof-of-Stake, reducing energy consumption by more than 99% and enabling validator rewards for staked ETH. Subsequent upgrades (Shanghai 2023 unlocking staked ETH withdrawals, Dencun 2024 introducing EIP-4844 / blob transactions) materially reduced L2 costs. ETH supply is not capped, but EIP-1559's base-fee burn can make the network deflationary during high-activity periods. Ethereum's competitive moats are the largest developer community, the highest TVL, and the most mature wallet and audit ecosystem. Ongoing critiques include high L1 gas costs, liquidity fragmentation across many L2s, and a complex multi-year roadmap (sharding, statelessness, danksharding). A spot ETH ETF was approved in the US in 2024.