Ethereum (ETH)
BasicsIn short The largest smart-contract platform. Developers deploy programs (contracts) that run exactly as written, powering DeFi, NFTs and most token issuance.
If Bitcoin is a ledger, Ethereum is a computer that everyone shares: anyone can upload a program and anyone can call it, with ETH paying for the computation. That openness is why most tokens, exchanges and lending markets were built here first. It also means congestion is felt as price — when demand spikes, fees do too, which is the problem Layer 2 networks exist to solve.