Jeff Bezos, chief executive officer of Amazon.com Inc., introduces the Kindle Fire HD tablets at a news conference in Santa Monica, California, U.S., on Thursday, Sept. 6, 2012. Amazon.com Inc. is updating its line of Kindle e-readers and tablets in a bid to stoke consumer demand as Google Inc. and Microsoft Corp. join the crowded market of machines challenging Apple Inc.?s iPad. Photographer: Patrick Fallon/Bloomberg via Getty Images