Amazon Profit Misses Estimates  SAN FRANCISCO (Reuters) - Amazon.com Inc &lt;A HREF="http://www.investor.reuters.com/FullQuote.aspx?ticker=AMZN.O target=/stocks/quickinfo/fullquote"&gt;AMZN.O&lt;/A&gt; on  Thursday posted a higher quarterly profit but its stock fell  more than 4 percent as the online retailer's results failed to  top Wall Street expectations.