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We all know that corporations are vacuuming up our personal data from every app we use and website we visit. Each app on our phones has hundreds or thousands of pages of personal info on us —literally (just ask the French journalist who asked Tinder for the information it had on her, and got back 800 pages of highly personal information).

Okay, fine. You might not care about that. But a new study from UW researchers should keep you up at night.

The study shows you don't have to be a big corporation to spy on people — anyone could do it, Wired reports. It just takes "time, determination, and about a thousand dollars."

Researchers at UW created an ad, paid about $1,000 to specify where the ad appeared, and in this way were able to track whether a particular device was at a particular location (the details are a little complicated and technical, but are spelled out in the Wired piece). In this way they were able to figure out the home and work locations of people using test phones.

As Wired explains: "An advertising-savvy spy," could "learn details about them like their demographics and what apps they have installed on their phone, or correlate that information to make even more sensitive discoveries—say, that a certain 20-something man has a gay dating app installed on his phone and lives at a certain address, that someone sitting next to the spy at a Starbucks took a certain route after leaving the coffeeshop, or that a spy's spouse has visited a particular friend's home or business."

Sure, there are limitations, and spies would have to know what they were doing: "The target would have to have a certain app open on their phone at the time they're being tracked, so that the ad can appear. And to track a specific phone, any ad-buying spy would have to know a unique identifier of the target phone, known as a Mobile Advertising ID, or MAID."

But someone who was highly motivated with a decent understanding of ads and technology could do it pretty easily. Wired notes that a domestic abuser could use this method, as could people with other hateful motives. Even using less advanced methods, researchers "were able to count the number of people with Grindr, or the Muslim-focused app Quran Reciter, installed at a target location without knowing any unique identifiers."

So what to do if you want to protect yourself from this spying? "Perhaps consider which ad-supported apps you use, when you use them, and what they reveal about you." Great.