"Strava’s data lets anyone see the names (and heart rates) of people exercising on military bases"

Wired:

His run, like millions of others around the world, was recorded through the Strava app. A heatmap of more than one billion activities – comprising of 13 billion GPS data points – has been criticised for showing the locations of supposedly secretive military bases. It was thought that, at the very least, the data was totally anonymised. It isn't.

By uploading an altered GPS file, it's possible to de-anonymise the company's data and show exactly who was exercising inside the walls of some of the world's most top-secret facilities. Once someone makes a data request for a specific geographic location – a nuclear weapons facility, for example – it's possible to view the names, running speeds, running routes and heart rates of anyone who shared their fitness data within that area.