I know PeterB is really pro-Microsoft but that Ars article is borderline cheerleading, an inaccurate headline with the fineprint later on. They did not sell 40 million licenses to end users and the numbers are well below Windows 7. It should also be noted that Windows 8 is typically selling at $15-40 right now compared to 2-3x the price for Windows 7.
Playing: Dark Souls 2: Scholars of the First Sin Watching: Mr. Robot