Amazon: Selling more online than its next 12 biggest competitors combined

A stunning stat on e-commerce (WSJ):

Amazon.com Inc. AMZN +0.85% sells more online than its next 12 biggest competitors combined, including Staples Inc. SPLS -0.50% and Wal-Mart, according to the trade publication Internet Retailer. Despite its greater online scale, Amazon continues to grow quickly and command a hefty share of new Internet sales. Its 30% increase in North American sales in the second quarter outstripped the overall e-commerce market and some competitors as well.