iBeacons use Bluetooth Low Energy technology to allow devices to detect signals within a range of 5-70 meters to enable location-based notifications and content. They consist of low-cost transmitters that broadcast an identifier to nearby smartphones, which can then trigger push notifications and app content. Major companies using iBeacons include retailers, museums, and airports for indoor positioning and promotions. The future of iBeacons includes expanding their use for indoor location and mobile payments.