Beacons are a form of technology that can transmit signals across what is generally a small radius. Think of getting a message on Twitter while walking by a coffee shop offering a discount. It might leave you SMH, but TBH that is nothing when you keep walking and your Instagram flashes another offer and then Uber hits you with a promo via text message.
Google of course is charging forward on this and they have the key assets with Google Maps and all of their other tools and investments.
Google has extensive coverage of Beacons and how to use them in the Google Developers Forum.