The note-taking analogy isn’t exactly bad or wrong, but… maybe I’m naïve, but I just don’t see where the incentives are to do anything with all these notes on our behavior beyond just mining it for possible marketing opportunities, which has just never bothered me. There are certainly classes of individuals, such as spies, very important journalists, celebrities, etc. who it might be worth it to tap into the raw data illicitly before it is purged, anonymized, summarized into oblivion. But that is true of things like the telephone network as well: it’s a data stream which is not guaranteed to be fully secure (cops can wiretap, or a crooked engineer at the phone company could gain access to listen in too). But those risks don’t seem to materialize in a way that matters to most people. So I’m as bothered by it as I am having a conversation in a restaurant: I wouldn’t yell out my SSN but overall I am pretty confident nobody cares about what I’m saying besides my intended listener.