Ecommerce Instore deli, bakery stand to benefit from online trend By Andy Nelson I n the United States, only a small percentage of groceries are purchased online. Estimates vary considerably, but it's safe to say that, as one industry analyst puts it, grocery is no air travel. The vast majority of us buy our plane tickets online, just as the vast majority of us get our groceries at a brick-and-mortar store. PEAPOD But as the news that Amazon is buying Whole Foods Market Inc. made dramatically clear, online's slice of the pie won't stay small for long. Rivals that are already ramping up their ecommerce sales will ramp a little faster. And for those who stick stubbornly to the foot traffic model, their jobs just got a lot tougher.