[Cobord]

Anyone could build such applications that they might hope become the biggest in the world, but there is still a conglomeration effect. You have centralization, but anyone can become the center. This is displayed by your "biggest in the world" winner takes all perspective. For decentralization, the graph of connectivity has to not have these large communities. There would be no single Twitter (unmoderated or otherwise) that is the biggest by far.

[threeseed]

But Web3 does not prevent or impede centralisation.

Look at OpenSea. They take the blockchain data and augment it with their proprietary data.