Ethereum (ETH) is the second largest cryptocurrency after Bitcoin. It is not just a digital currency; it is the fuel or "gas" needed to operate the Ethereum network, which is a decentralized platform that allows developers to build decentralized applications (dApps) using smart contracts. Ethereum was launched in 2015 by Vitalik Buterin, and it has revolutionized the blockchain world with its potential that goes beyond just transferring value. Smart contract technology is the foundation for many decentralized applications in fields such as decentralized finance (DeFi), non-fungible tokens (NFTs), and more. Ethereum features an active development community that continuously works on developing and improving the network, and it has seen many significant updates aimed at increasing its efficiency and scalability.