Amazon reported third quarter results on Thursday afternoon, with much better than expected net income of $2.88 billion, on sales of $55.6 billion (up 20 percent). But the stock is down on the news — albeit after rising 7 percent during the day on Thursday — declining 8.5 percent or about $150 a share in the first hour of trading on Friday. The reason is that investors didn’t like the forecast sales growth for the big fourth quarter of only 10 to 20 percent (with operating income expected to be anywhere from flat, at $2.1 billion, up to $3.6 billion. […]