Every time you tag your location on Instagram, you willingly make that information public to your followers. We know this because we do it on purpose so that our friends, exes and former high-school rivals know we’re at whatever exotic destination they’re NOT at. In isolated instances on any single post or story, this location sharing doesn’t seem too risky. But what if one of your followers had been diligently tracking and recording every single location you had ever posted about on Instagram since you first opened your account?

That’s exactly what the new app Who’s in Town does, and it compiles all that information into a handy interactive map any of your followers can access. According to Wired, users who download the app are provided with a comprehensive map showing every location everyone they follow has tagged in Instagram posts and stories. Who’s in Town pulls data from every post since the beginning of a user’s account, as well as geotags from stories posted starting that day.

“The amount of data is insane,” said the app’s creator, Erick Barto. “It’s the equivalent of you going through every single story and writing down every single location, just consistently all the time.”

Depending on how actively any given user tags their location on Instagram, Who’s in Town could provide sensitive information about a person’s daily habits, routes and schedules, all collected in one place. This wealth of information could leave Instagram users vulnerable to stalking, home invasion and other very real privacy concerns.

The app’s creator is well aware of these risks, and that’s the point. According to Barto, he made Who’s in Town with the purpose of revealing just how vulnerable the average user makes themselves on social media.

“People don’t realize what they’re sharing,” he told Wired. “They’re [operating under] the false assumption that this information is only going to a few people … but it’s public.”

Instagram is currently reviewing the app, and Barto doesn’t expect Who’s in Town to be particularly long-lived. If anything, Barto hopes the controversial app will encourage social-media platforms and users to revise their approach to information sharing.

In the meantime, Barto is aware that he’s putting users at risk, at least temporarily. “If it does get taken down, that means that whatever data is shared with you by your friends, you have no rights to that — and we know that, of course.” Kind of a dramatic way to teach us all a lesson about internet safety, but thanks?

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