Amazon’s technology platform is massive and powerful enough to support not only sales of its own items but also those of third-party small and large businesses, which integrate their products into Amazon’s Web site and use its order entry and payment systems to process their own sales. (Amazon does not own these products, and ship- ping is handled by the third party, with Amazon collecting 10-20 percent on the sale). This enables Amazon to offer an even wider array of products than it could carry on its own while keeping inven- tory costs low and increasing revenue. Amazon has further expanded its product selection via acquisi- tions such as the 2009 purchase of online shoe shopping site Zappos.com, which earned $1 billion in retail sales in 2008 and gave the company an edge in footwear.