Hahaha, well... I don't think anyone could sell the data, it's already public on a blockchain :)

That's the beauty of the blockchain - no one owns the data like how FB owns all your data on FB. It's all given freely, all the time, so why would anyone buy it?

One thing people might do is harvest and analyze the data then sell those results. That's being done by groups on pretty much every blockchain already I imagine.