A staggering variety of clandestine trackers have been found in popular Android apps, reports The Intercept.

Researchers at Yale have documented the proliferation of tracking software on smartphones, finding that weather, flashlight, ride-sharing, and dating apps are infested with dozens of different types of trackers collecting vast amounts of information to better target advertising.

“Researchers identified 44 trackers in more than 300 apps for Google’s Android smartphone operating system. The apps, collectively, have been downloaded billions of times.”

One type of script allows whoever owns the website you’re perusing to literally watch whatever you’re doing. Called “session replay” scripts, these services record everything you type, where you move your mouse, and more.

This isn’t anonymized data collection–it’s very personal, say The Intercept.

It’s “as if someone is looking over your shoulder,” write the Princeton computer science researchers.

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