Web3 is supposed to be the next generation of Internet.
Many answers correctly point that web3 will be about decentralization.
However most of the answers tie web3 to blockchain technology, which I think is very wrong. To find the exact reasons please check this article -
DINO (Decentralized In Name Only) Vs. True Decentralization
In my opinion decentralization is much bigger than blockchain technology.
In our ‘decentralized web’ project we use a blockchain instance as a support element only.
The backbone of our web3 implementation is the direct user to user communication.