A shopper walks past your store. They weren’t planning on stopping in until a link to your latest offering hit their phone. Along with the offer, they get images, the right coupon, reviews, and a little marketing magic.

Now that billboards, window displays, and other signage are the norm, Bluetooth beacons are adding that extra kick to grab attention, triggering notifications as a user comes within proximity to a location. For small and medium businesses, beacons are a uniquely practical trend. Owners need only purchase one beacon in order to begin seeing results. Simply place it near the store entrance or anywhere you want to reach customers.

Beacons have been generating buzz since 2013, when Apple AAPL +1.88% first introduced iBeacon technology. And while it may have appeared for a time that this new way of connecting with customers might be slow to catch on, today it’s catching fire. This year began with BI Intelligence reporting that beacons would be driving $44 billion in retailsales by 2016, up from $4 billion this year. Then last month came the big news that Apple and IBM have teamed up on a host of new apps incorporating analytics and iBeacons. And just last week, Ad Age reported on the impending reinvention of retail by digital technology, as the physical and digital worlds converge in stores.