Thanks in large part to the success of the Kindle e-reader as well as brisk holiday sales, Amazon has reported a major spike in fourth-quarter profit, boosting net 71 percent to $384 million. Sales for the Seattle-based company also rose 42 percent to $9.52 billion. The company didn’t release the numbers for Kindle sales, but Founder Jeff Bezos said, “Millions of people now own Kindles. And Kindle owners read a lot. When we have both editions, we sell six Kindle books for every 10 physical books.” Though Wednesday's release of Apple’s iPad has thrown the future success of the Kindle into question, Amazon executives say they expect sales between $6.45 billion and $7 billion for the current quarter.