“One search turned up more than a dozen people visiting the Playboy Mansion, some overnight. Without much effort we spotted visitors to the estates of Johnny Depp, Tiger Woods and Arnold Schwarzenegger, connecting the devices’ owners to the residences indefinitely. If you lived in one of the cities the dataset covers and use apps that share your location — anything from weather apps to local news apps to coupon savers — you could be in there, too. If you could see the full trove, you might never use your phone the same way again.” At the end of a decade when we embraced the tools and tech that enable us to voluntarily share everything about ourselves with governments, corporations, and irritated friends, the NYT investigates the smartphone tracking industry. One Nation, Tracked.