At the Build 2015 Developer Conference currently taking place, Terry Myerson, executive vice president of the Microsoft operating system, said a very big goal for the company:
"In two to three years, Windows 10 will be available on 1.000.000.000 (billion) devices." 
This promise went straight to developers to consider investing in Microsoft's upcoming operating system. The benefits from a huge database of Windows users offer huge financial incentives to developers.
Myerson in his speech at Build 2015, reported that with current estimates on Google Play it appears that Android KitKat usesfrom “500 million devices.” He also added that the latest version of iOS 8 is used a lot is less than Android.
In this spirit, Myerson also announced that charges are coming through the telephone service provider.
What does this mean; Users of all devices running Windows will be able to shop without credit κάρτα. Ο λογαριασμός από το Windows Store will be delivered to them with their phone bill.
Microsoft says support for carrier billing is currently only for smartphones, but it will soon be available for computers and tablets.
