During its Build 2015 developers conference opening keynote in San Francisco, Microsoft revealed that it is predicting that there will be one billion devices worldwide running its new Windows 10 platform. That includes laptops, desktop PCs, Windows phones, Xbox One, its own HoloLens AR system and more.
That, it claims, will make the platform the most used in history - not only amongst its own Windows releases over the years, but also beating ecosystems and operating systems from Google and Apple.
As Build is mainly for developers and analysts, much of the talk about Windows 10 was about how applications can be built that will work across a vast array of devices, even including Raspberry Pi.
Apps will resize to different windows, so can be used on a phone screen but also tablet or even a TV through Xbox.
Developers were also told that they could add other Microsoft services within their own apps, including Xbox Live support to add achievements for software applications that aren't just games.
The Windows Store will also undergo a refresh, including the ability to pay for apps through carrier billing and other payment systems around the world - not just debit and credit cards. There will also be a new Windows Store for Business which will provide apps specifically for businesses and schools. These will even be able to be paid for through other means, such as purchase orders.