Yes, Google is willing to pretend to know only what you tell them to pretend they know. After Chrome made any login to a Google service also log you in on the b

Yes, Google is willing to pretend to know only what you tell them to pretend they know. After Chrome made any login to a Google service also log you in on the browser, I decided to use a non-Google browser for any Google service. I switched over to another computer, which had a non-Google browser (FF) on it, made sure all cookies, etc., were deleted, and went to YouTube. YouTube said I wasn't logged in. And yet, YouTube's recommendations were combination of obscure items of interest only to me that it had been recommending on the other computer. It was telling me to log in but already knew who I was. Presumably it matched my IP address, but if I had used it for a while from a different IP address, it would have been able to match my usage and identified me that way. And if not that, one of my many Google-employee neighbors mentioned that they record your typing rhythms when they can, and those rhythms eventually uniquely identify you. So when Google's "here's all we know about you" purports to reveal all, it shows you what they think of you rather than what they actually know about you.