Investor enthusiasm for Amazon.com Inc (AMZN.O) is pretty consistent: the stock tends to rise, even though the company isn’t consistent about making profits. On Thursday it posted second quarter profit of $92 million on sales of $23.19 billion, only its third quarterly profit since the first quarter of 2014. Amazon has reported an annual net profit in 10 of its 18 years as a public company, and only twice in the last four years.