Beacons can be used to power indoor maps, payments services, and location-sensitive product catalogs. There are many different beacon hardware vendors and systems — including Apple's iBeacon system — but they all share some basic characteristics. Namely, they allow retailers and event organizers to efficiently communicate indoors, without a need for GPS.  Beacons — low-cost devices that communicate with smartphone apps indoors — will begin exerting a significant influence on US retail sales in 2015.  Beacon-influenced sales volume will ramp up quickly, as many forms of in-store marketing take up the technology, including couponing. iPhone and Android smartphones are compatible with this technology. We estimate that beacon-triggered messages could directly influence up to $4.1 billion of total US store sales this year (or .1% of sales volume at top-100 retailers). That figure will grow 10X in 2016.

http://uk.businessinsider.com/beacons-market-and-retail-opportunities-2015-2?r=US