If anyone remembers, back in March of this year, Apple acquired a company called WiFiSLAM. Here's an article that talks about
that acquisition. It's not hard to put 2 and 2 together and conclude that this is somehow related to iBeacon. I would guess that initially, the uses would be pretty simple - like having iBeacons placed in a mall so that you can use your iPhone to navigate inside, finding specific stores, or restaurants. But then you can easily have them alert people to sales or deals. Also, since the iPhone itself can function as an iBeacon, I would think it would be useful in finding other people - like when you need to meet-up with friends at a packed concert for example.