I looked up Wikipedia's definition:
Web3 (also known as Web 3.0[1][2][3]) is an idea for a new iteration of the World Wide Web which incorporates concepts such as decentralization, blockchain technologies, and token-based economics.
That sounds like a bunch of BS and sounds very familiar:
it's mostly used as buzzword.
They are trying to make it a hot topic just as NFT was a few months ago or ICO or a few years ago
They're now trying to add different money-grabbing buzzwords into one new name.
This explains a lot:
The term "Web3" was coined by Polkadot founder and Ethereum co-founder Gavin Wood in 2014
Altcoins (AKA shitcoins) were solely created to make the creator rich, and it looks like this new hype is just more of the same.