Ryan Shadrin

Would you trade your location data for an in-store discount? That's the idea behind Swirl, a mobile app now being used by retailers like Kenneth Cole and Timberland in Manhattan and other cities. The app can target those with a declared interest in designer duds or tough terrain footwear, and even if they've perused a specific section of those stores. At the Kenneth Cole in Grand Central Station recently, shoppers who downloaded the Swirl app and allowed it to track their location were notified of a 20 percent discount on full-priced merchandise.