Currently, online sales hover around 7% of the total. But with 73 million millennials taking over the coveted 20-40 year-old spending space, it's quite possible that he'll be right. 

Consider, too, that millenials are 250% more likely than baby boomers to shop online.

"Shopping can be both fun and fast," writes Niraj Shah -- WayFair CEO. "Driving several miles to a big-box store in hopes that they might have just what you are looking for is neither." 

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