Amazon.com Inc is the leading internet retailer in the US and worldwide. In 2011, it had net sales of $21.9 billion and a 16.9% share of the US internet retailing market. Amazon launched its Kindle e-reader in 2007 and has since expanded its private label offerings to include electronics accessories and home goods. While facing competition from retailers like Walmart and Barnes & Noble, Amazon maintains its leading position through continuous innovation, expanding product selection, and customer-centric services like free shipping.