According to the most recent report from the U. S. Department of Commerce, the amount of e-commerce has been increasing rapidly from a meager $35 billion in 2001 to a whopping $164 billion in 2010. It accounts for as little as1.1% of the total retail sales in 2001 to as much as 4.2% in 2010. Its growth rate maintains steadily at an incredible 19.3% a year on the average in the past ten years. During this short period of time the e-commerce has grown from its infancy to its maturity. The annual data are shown in Table 1 (U.S. Department of Commerce, 2011).