These days, people seamlessly switch between their phones, their computers, and local stores when making purchases and returns. Just think about all the websites and apps that now offer in-store, pickup, and shipping options, letting customers know whether an item is in stock or not. In this omni-channel world, customers expect to see digital ads in retail spaces frequently. Retargeting ads remind customers of items they’ve viewed in the past. Banner ads and clever graphics call out promotions on retail websites. Digital advertising is already thriving online. But brick-and-mortar operations h…