It's been a fabulous year so far for Amazon.com (NASDAQ: AMZN). While the S&P 500 has gained less than 4% in 2018, Amazon shares have skyrocketed 50%, driven by its growing dominance in the realm of e-commerce and strength in the company's industry-leading cloud computing business.Investors will be looking closely at the numbers when Amazon reports the financial results of its 2018 second quarter on Thursday, July 26, after the market close.