Bluetooth wireless location-based marketing technology
I've gotten these in London a few times. When you are walking by the movie theaters in London, you'll get a phone message, and when you look it came via Bluetooth. Inside the message is usually a coupon for discounted concessions. Some of the music stores do this as well to push new releases or videogames.
It relies on people like me who never turn off the Bluetooth on their phone.
It's another example of a specialty ad network that ProximityMedia has created.