“Web2 refers to the version of the internet most of us know today. An internet dominated by companies that provide services in exchange for your personal data. Web3, in the context of Ethereum, refers to decentralized apps that run on the blockchain. These are apps that allow anyone to participate without monetising their personal data. Web3 benefits Many Web3 developers have chosen to build dapps because of Ethereum’s inherent decentralization: Anyone who is on the network has permission to use the service – or in other words, permission isn’t required. No one can block you or deny you access to the service. Payments are built in via the native token, ether (ETH). Ethereum is turing-complete, meaning you can pretty much program anything”

Source : Web2 vs Web3 | ethereum.org