Windows 10 has 500 million monthly active devices, Cortana boasts 140 million and lets developers in

Last September, Windows 10 boasted more than 400 million monthly active devices, which is nothing to scoff at. But today the company's CEO, Satya Nadella, has announced that the operating system has passed 500 million monthly active devices. Those are, as the name implies, devices on which Windows 10 was used at least once in the past month.

The growth in Windows 10 adoption has stalled after the free update period for the OS ended, and as a consequence Microsoft has revised its expectations Cheap Phone  for hitting the 1 billion number. While initially that was said to happen by next year, it now claims it will reach it sometime after 2018.

Cortana, the company's own entrant into the increasingly crowded virtual assitant space, now boasts more than 140 million monthly active users. And China Phone those are people that third-party developers can now target through the use of the newly released Cortana Skills Kit preview.

It's like a Software Development Kit (SDK), but for Cortana. So any developer can theoretically build a new "skill" for the assistant, and it will work across devices and operating systems that Cortana is available on - Windows 10, iOS, Android, and new standalone Cortana products such as smart speakers.