If you think pop-up shops are, well, popping up all over the place, you’re right. They’re short, they’re sweet, and, when done correctly, they make an impression long after they’ve left the building.When it comes to cooking up tantalizing consumer experiences, retailers of all stripes are embracing an old idea that, paired with technology, feels new again: the pop-up store. The concept of the temporary shop, which was born in the late 1990s in Los Angeles, is so popular it’s baked into the modern consumer experience—as ubiquitous as markdowns and email blasts. According to IBISWorld, the number of pop-up stores in the United States grew 16 percent from 2009 to 2013. What’s behind the pop-up boom? The format’s potential to reach new demographics sans serious investment may be its most obvious charm. But today’s retailers are also using ephemeral shops as labs for t