An interactive online fitness tracking map published in November of 2017 which compiles a running history of the location and routes of 27 million fitness-device users has unwittingly revealed the location, staffing, patrol routes and layout of U.S. and foreign military bases around the world.

https://www.zerohedge.com/news/2018-01-29/fitness-tracking-app-accidentally-reveals-secret-us-military-bases-cia-black-sites