If you use the popular Facebook Messenger app, the people you chat with could be stalking you. That's because the app shares your location by default and creeps could use that data to track your location throughout the day.
Harvard student Aran Khanna wanted to see just how much location data your Messenger reveals. As part of his investigation, he created a Google Chrome browser extension for the Facebook Messenger page. It collects all of the location data in your chats and plots it on a map.
And if this isn't already starting to get a bit weird, the first thing I noticed when I started to write my code was that the latitude and longitude coordinates of the message locations have more than 5 decimal places of precision, making it possible to pinpoint the sender’s location to less than a meter.
The extension made it possible for Khanna to find out the location of his brother's friend's dorm room at Stanford by using location data for chats that took place late at night. This might not seem like a huge problem if you only chat with close friends and family members. But, what about those old high school friends or former coworkers you haven't seen in ages? If you send any chat message them, they instantly have access to your exact location data, too.
It gets worse. The app could even be sharing your location data with people you don't know at all. If you're involved in a group chat with people you're not friends with, they can still access the location data attached to your messages.