At BUILD 2017, CEO Satya Nadella announced that Windows 10 now powers half a billion active devices worldwide. It’s directly relevant to mobile, of course, because the same ecosystem powers all of these, whether desktop, laptop, hybrid, tablet, Xbox or… phone. My own estimate for the number of truly active Windows 10 Mobile users was seven million a while ago, so let’s assume a few more people have now upgraded older phones – call it a round ten million. Which is only 2% of the Windows 10 total, but hey, the numbers do add up. Even if the original target was one billion users in the first couple of years.