As New York City looks to upgrade its phone booths, the boxes may be getting more technology than many citizens realize. This weekend, a Buzzfeed investigation found approximately 500 advertising beacons in Manhattan phone booths, all installed without a formal approval process or public comment period. In response to the report, the city has announced it will remove the beacons "in the coming days."

Beacon devices work over Bluetooth, typically looking for phones running a Beacon-enabled app (typically from a store or brand) and sending a push notification once that phone is in range. If you're walking past a Gamestop, for instance, you might receive a push notification through the Gamestop app that a nearby store is having a sale. At the same time, the Beacon collects anonymized data on nearby app users, and sends it back to Gamestop HQ for marketing purposes.

It's still unclear how NYC's phone booth beacons were planned to function. They were installed by an advertising company called Titan, which also made a test model for the city's next-generation payphone contest, but Titan maintains the beacons were only being used for research and maintenance purposes. Still, based on Buzzfeed's research, hundreds of them are already sending out working Bluetooth signals.

10/6 1:49pm ET: Updated to include the city's planned removal of the beacons.