That's why I believe a lot of value all these trackers provide to various companies is not so much the typical 'buy this product now' pop-up that you're thinking, but instead more nefarious value-adds.

Maybe that mortgage or car loan rate you applied for came back a little higher than others would have received on the same day. Perhaps that collection agency decided they wouldn't discount the medical bills because they know 'you can afford it'. I've seen several sites give me one price when I was logged in without an ad blocker, and then a lower price after clearing my cookies.

There is no way insurance companies aren't paying huge amounts of data to calculate rates offered to individuals based on thousands of data points. I imagine the government itself would be able to take advantage of user data in all sorts of clever ways - everything from solving crimes to catching tax cheats to provide better and cheaper background investigations for the millions who require it.

Companies interviewing candidates could save thousands on each potential hire if they could quickly have an algorithm avoid the 75% of candidates they wouldn't consider hiring anyway.

There are just so many ways companies can statistically make a few extra percent here or avoid an expensive loss there, it will be used until the government disallows it, which apparently isn't going to happen anytime soon in most countries.

When you grab a bottle of dish soap off the shelf, do you select the same one each time because you prefer it for reasons you can't quite articulate or do you grab whatever's cheapest because they're basically all the same?

The numbers coupled with lack of factual evidence of effect is staggering. I have a lot of distrust in the business. It’s about as accurate as Nielsen.