Amazon is using purchase data to sell targeted ads, which is creepy, but not because they've invented a mind-control ray

Amazon is building out its ad-targeting program to allow for ad-buys like "people near a physiotherapist's office who've bought a knee-brace," and reports that the ads are incredibly successful.

What's interesting about Amazon's reference customers for the efficacy of their program is how trivial they are: figuring out that knee-brace buyers who live near a physio might patronize that physio is not exactly rocket surgery. There are a ton of these "signals" that are probably a good predictor of future actions: if you buy a baseball bat and ball, you might travel to a nearby park to meet some friends in the near future; if you look up car ratings, you might buy a car soon; and so on.

The insights are trivial: what's sophisticated is the targeting after the insights. In the age of paper car-buyers' guides, the only way to advertise to potential car-shoppers was to buy ad-space in those guides. You couldn't -- for example -- know when people were talking about buying a car with friends and show them an ad there. Surveillance capitalism has bequeathed upon us vastly improved means of identifying people who have some rare, widely diffused trait (say, people who recently called to price out a refrigerator repair and might be in the market to buy a new fridge, something the average person does between 0 and three of four times in their entire lives).

But what surveillance capitalists do is conflate their ability to identify people who share a trait with their ability to identify traits to look for in people.