If you notice that display racks this holiday season are nicely scented, it’s not just shops are tidier at year’s end. Scents like citrus and floral can make you linger and stay alert in the shop to buy more. Marketers believe scents do sell, with an increasing number of scientific studies backing such claims, that the whole act spawned a new marketing sub-industry: scent marketing. It reminds us of germ warfare, an unseen weaponry that has your wallet in the crosshairs.