Now Apps Can Track You Even After You Uninstall Them

If it seems as though the app you deleted last week is suddenly popping up everywhere, it may not be mere coincidence. Companies that cater to app makers have found ways to game both iOS and Android, enabling them to figure out which users have uninstalled a given piece of software lately—and making it easy to pelt the departed with ads aimed at winning them back.

Adjust, AppsFlyer, MoEngage, Localytics, and CleverTap are among the companies that offer uninstall trackers, usually as part of a broader set of developer tools. Their customers include T-Mobile US, Spotify Technology, and Yelp. (And Bloomberg Businessweek parent Bloomberg LP, which uses Localytics.) Critics say they’re a fresh reason to reassess online privacy rights and limit what companies can do with user data.

Uninstall tracking exploits a core element of Apple Inc.’s and Google’s mobile operating systems: push notifications. Developers have always been able to use so-called silent push notifications to ping installed apps at regular intervals without alerting the user—to refresh an inbox or social media feed while the app is running in the background, for example. But if the app doesn’t ping the developer back, the app is logged as uninstalled, and the uninstall tracking tools add those changes to the file associated with the given mobile device’s unique advertising ID, details that make it easy to identify just who’s holding the phone and advertise the app to them wherever they go.

At its best, uninstall tracking can be used to fix bugs or otherwise refine apps without having to bother users with surveys or more intrusive tools. But the ability to abuse the system beyond its original intent exemplifies the bind that accompanies the modern internet, says Gillula. To participate, users must typically agree to share their data freely, probably forever, not knowing exactly how it may be used down the road. “As an app developer, I would expect to be able to know how many people have uninstalled an app,” he says. “I would not say that, as an app developer, you have a right to know exactly who installed and uninstalled your app.”

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