So here's a question: Is a store really a marketplace? It seems to me that Amazon, Target, Macys, etc, do a lot of curation and editorial work with regards to standards of production and marketing for items in their stores. Isn't that more akin to publishing?
I think the grey area and critical zone is this: Should a company be allowed to advertise their ecosystem/playground as akin to a "marketplace" when what's really happening, is that they are tightly controlling the product and harvesting the information for themselves? Seems like a bait and switch to me! ("Your margins are our opportunities," is the most fundamentally aggressive business statement I can possibly imagine, and Jeff Bezos said it!)
Apple, Amazon, and YouTube all seem to fall into this general pattern: A "marketplace" or "ecosystem" which is less bazaar and more their tightly planned cathedral. "Partners" who are put upon, data-analyzed, and sometimes cannibalized. This pattern seems to be very widespread, and it only stands to reason, given the tremendous increase in the ability of companies to leverage technology to harvest such data in their own playgrounds.