I don't get what changed? We've knows Facebook tracks everything, we've known Google does the same thing. If you've ever developed anything in messenger even today, it's amazing how much information is given. We know all these sites track everything you do outside of Facebook too. Everyone has been trying to get them to stop, we know it's illegal to build a profile on someone but Facebook gets around that by building…
One thing I am confused with all the data collection that is going on (and it obviously costing them $ and some reputational risks) is not really helping them to produce decent ad targeting. I am not even surprised by how bad FB ads are most of the time but even Amazon that has 20 years of my purchase history is amazingly bad: I already bought 4 Elixir programming books and looking to buy new books when they come out…
If I'm starting a new hobby or wanted to buy a present for someone with different interests, I would be very annoyed if results were hidden from me because of a name clash with a product from my purchase history.
A good product search isn't personalized, and doesn't try to predict what I want. It just shows the results in a sensible manner, and lets me use categories and keywords (in addition to user reviews, price, availability, etcetera) to filter the results.