IOS devices using iBeacon send out signals through Bluetooth. If the signal reaches multiple Apple devices at the same time, each of those devices will display the notification at the same time. iBeacon will display a notification customized to individual users is when a user has ordered an item online and has come to an Apple Store to pick it up.
In-store location technology raises privacy concerns. Apple said that it does not collect information about shoppers inside its stores. The company said notices are triggered when the app senses a location beacon nearby, without Apple's beacon needing to even know you're there.
Google, Microsoft and other tech companies will likely follow suit with their own location technology.