|Why They're Hot:
Mobile traffic at specialty e-retailer Fathead hit 42% in late 2012. But the merchant's m-commerce site for smartphones was not fully meeting customers' needs, and the merchant had nothing for tablet shoppers. That's why Fathead, which sells life-size wall decals of sports stars and other graphics, moved to responsive web design, building one site with one code base adapts to fit any size screen, from smartphone to smart TV. Ten in-house technology staffers spent 1,500 hours developing the site, which launched in late 2012. Comparing the first half of 2012 with first half of 2013, smartphone conversions rose 90% and revenue jumped an astonishing 538%. "It's a win for us," says Michael Layne, director of Internet marketing. Fathead also offers an augmented reality mobile app.