Beacon buzz is everywhere, but what exactly can beacons do ... and not do? How accurate are these little transmission devices, who can they reach and how, and what can you do with this information? How many should be used within any given area and how does a marketer decide which apps technically work best with which beacons? Greg Ratner, director of technology at Deep Focus, outlines the practical realities of beacon technology and the essentials you need to know, including the capabilities – and limitations – of beacons.