After BuzzFeed revealed late Sunday that a digital advertising firm, Titan 360, was using public pay phones in New York City (yes, they still exist) to host Gimbal Bluetooth tracking beacons, the mayor's office has now ordered them to come down.
The beacons can be used to log nearby phones. Bluetooth addresses and mark the date, time, and location where they are seen. As such, the beacons can be used as a way to track physical movements of cellphone users, potentially allowing advertisers to serve those phones customized spots. (Users who have Bluetooth turned off on their phones will not be seen by the beacons.)