Some years ago, I watched some historical TV show (could be Rome?) where one of the characters has been diagnosed with some disease, so I wondered if they knew how to properly diagnose it at the time the show was set at. So I used Google to search for the disease to get to its Wikipedia page. Then I almost forgot about it.

For months after that, Google bombarded me with the links to the disease and cures and remedies and whatnot.

I remember even seeing that at my kid's gaming PC, and I don't remember ever logging in to my Google account there. We only shared the same IP in the household.

That's pretty anecdotal, I know, but that's what there is.