Web3 applications either run on blockchains, decentralized networks of many peer to peer nodes (servers), or a combination of the two that forms a cryptoeconomic protocol. These apps are often referred to as dapps (decentralized apps), and you will see that term used often in the web3 space.

Web2, launching in 2004 was revoutionary in allowing people to connect socialy through websites such as Facebook.

With Web3 however, users will own there own content through decentralization. It will allow users to own the web!
Think of it like this, if I bought a digital card (NFT), I own a certain ID in the cards that are producuded and it is backed by smart contracts and the blockchain to verify its mine. No one else will have that "ID" on there card though.

A blockchain is a distributed database or ledger shared among a computer network's nodes. They are best known for their crucial role in cryptocurrency systems for maintaining a secure and decentralized record of transactions,but they are not limited to cryptocurrency uses. Blockchains can be used to make data in any industry immutable—the term used to describe the inability to be altered.

Cryptocurrency is a digital or virtual currency that uses cryptography (encryption techniques) to secure and verify transactions and to control the creation of new units. It operates independently of a central bank or government and uses a decentralized system of record-keeping called a blockchain to maintain a public ledger of all transactions.