I don't work in advertising so I can't say for certain what people do and don't do. But yes, that seems like one useful data point. But perhaps more interestin

I don't work in advertising so I can't say for certain what people do and don't do. But yes, that seems like one useful data point. But perhaps more interesting is the ability to determine that User X is trying to clear their data for Wayfair, Amazon, and Home Depot, but not Target and not Lowe's. I could imagine some interesting analysis with that data, even if only in aggregate. There's also no prohibition that I can see in the Privacy Policy against things like fingerprinting your device, building a shadow profile on you, and exposing that data via some API with an "anonymized" identifier. I suspect that the ability to determine something like "owner of mobile device 123455321 is privacy-conscious" might in and of itself be a useful feature for targeting ads.