Google's ads do not seem particularly well targeted, even with the 20+ years of information they have collected on me. I feel like I've given up way, way too much of my privacy for what I've been given in return.

By far, the best targeting is to show an ad as I explicitly search for something and that's not going to go away for them anytime soon.

> which is only effective with good targeting to the fitting users

You talk like that’s the only way. Instead of fitting the ad to users, we could fit the ad to the content, like we’ve always done. Tracking users isn’t necessary.

> is only effective with good targeting to the fitting users

This isn't true in my experience. When I was an affiliate marketer in a past life, it was extremely profitable to promote health and fitness products on generic search terms such as "basketball" and "football scores". User demographic data wasn't required.

Unfortunately, Google decided that they don't like affiliate marketers.

Of course we'll never know how much of a difference targeting makes to the bottom line, but I doubt that it's huge.

Google's revenue comes from people searching for queries like "good traffic ticket lawyer", and from competitors bidding up each others' brand names. It would probably work just fine without targeting.