Last week, Amazon reported a blow-the-doors-off quarter. One leading Wall Street analyst described the results as a “game changer.” Going into the earnings report, analysts expected Amazon’s AWS cloud computing business to post revenue growth of about 30%. Instead, AWS delivered revenue growth of 37%. That is an extraordinary rate for the market leader in cloud computing.

AWS controls roughly half of the U.S. cloud computing market. Moreover, despite aggressively increasing capital spending, Amazon expanded operating margins. That margin improvement went a long way toward alleviating Wall Street’s concerns that the company was overspending on cloud infrastructure.