All joking aside, the launch of Apple’s iPad may be a significant rival to Amazon’s profitability. But for now, the online book retailer is enjoying a big boost in profits thanks to the Kindle. The Seattle-based company said Thursday that strong holiday sales sent net profits soaring 71 per cent during the fourth quarter of 2009 to $384 million, while sales rose 42 per cent to $9.52 billion. Amazon did not release a figure for Kindle sales, but back in October Amazon said the e-reader was their top selling item. “Millions of people now own Kindles,” said chief executive Jeff Bezos.