One thing I've wrestled with with the rise of online news and its effects on physical newspapers is how much I miss certain things about the physical newspapers. I don't miss the physical format, but I do think the old-school paper newspapers were much more enjoyable to read than most online equivalents.
At some point I realized that one major issue is that advertising in many of the paper copies was based around content area: if I went to the performing arts section, for example, it would be filled with ads for performing arts events. I loved this as it was actually useful and informative to me. I went to that section looking for performing arts, and that's what I got.
In online news, though, if I go to a performing arts, I don't get informative, unintrusive ads for performing arts events in my area, I get bombarded with random ads for things unrelated to what I'm looking at. Even if, say, earlier in the day I was looking for shoes, I don't want to see ads for shoes if I'm browsing performing arts, I'm interested in performing arts.
What you're talking about is a broader observation about identification of individuals per se versus patterns of interests and behaviors. However, I'd argue that a major failure of online advertising (with very important exceptions, including Google, DuckDuckGo, and many other places) is the recognition that what matters for ads is interest at any given moment, and not interests at any other time. I suppose someone might say "but a good ad is something that gives you what you are interested in even if you might not recognize it" but this is really difficult to get right, especially given that my interests in a given moment can shift from minute to minute.
If I'm moving from, say, shoe shopping to, say, performing arts, I'm deliberately moving my attention away from the former to the latter. Showing me ads for shoes is something that's specifically going against my current attentional goals. It's like saying "hey Honey, I'm done in the kitchen and am going to go into the garage to work on something" and then having some random stranger show up and pull you back in the kitchen.
This seems to be a fundamental screwup with a lot of online advertising: the failure to recognize that I'm functionally a different person from moment to moment, and when I move from one page to another there's a reason for that.
Email surveillance is maybe going even further in a worse direction, in that it's even more decontextualized and time-independent. Part of the brilliance of Google search ads, and things like DuckDuckGo, is that they catch you exactly in that moment when you're looking for something on a specific topic. Newspapers and everywhere else needs to take better advantage of that paradigm. Show me what I'm looking for now, don't take a shotgun guess at what I might want based on what I was doing in the past.