I think blockchain will help us with this.

It would be interesting to create an HN bot that replies exactly this to every top submission, then track the up/downvotes

For the payments layer, yes, but not for storing the actual marketplace data. Blockchains aren't great for storing data apart from maintaining a transaction ledger.

When we started building OpenBazaar we specifically avoided using a blockchain apart from Bitcoin for payments. It was the right call I think. There are plenty of other decentralization tools to use apart from blockchains, like IPFS, which OpenBazaar 2.0 is built on top of.

As I understood, there are 2 different apps: "Find it" and "Image search". If yes, .. why?