Curve is an exchange liquidity pool designed for extremely efficient stable-asset trading. Its main goal is to let users and other decentralised protocols exchange stable assets (stablecoins, different kind of Bitcoin on Ethereum) through it with low fees and low slippage.
Curve is fully decentralized and all decisions about the protocol are taken by CRV holders.
Unlike exchanges out there that match a buyer and a seller, the behaviour of Curve is different, it uses liquidity pools. Liquidity providers deposit one or more stablecoins in a Curve pool and receive Curve LP tokens. Liquidity providers receive 0.02% of trading fees currently and are also incentivized with CRV token.