This NFT explainer, linked here already by many, is amazingly good:
https://www.youtube.com/watch?v=YQ_xWvX1n9g

That said, this sentence is just art:
> This is what makes [NFT] enthusiasts so deeply unreliable: they have meaningful financial stakes in an intangible, volatile thing that exists entirely as a collective ideoform.

I promise the rest of the video is very clear and easy to understand, cuts through the bullshit like knife through butter. But that sentence... that sentence is *dense*.