Always a confusing and not very useful terminology.
(Too many people wanted to claim that their thing is Web3.0)
There's a lot of talk of it as blockchains, decentralized finance and apps and metaverses.
Perhaps that's better called Web3 though.
Just a conceit for some interesting articles by PhilWaineright on API driven applications. Read with WebServices, WebTwoPointZero (obviously) and the PlatformWars blog] http://platformwars.blogspot.com blog]
Timely since there's a new wave of opening up APIs (Alexa, DaveWiner trying to get people to clone the Google API, etc)