Why "Windows 10"? Windows 9 was the "natural" name for this release, Terry Myerson said, and was indeed the original name. But after joking about a few fake names—like Windows One—he noted that this isn't an incremental release. It's a major new Windows that will run on everything from headless Internet of Things devices to phones to tablets to PCs to the Xbox to the cloud. They really wanted to segregate it from current Windows versions.
Continuum: One major new feature. Of course, Microsoft still needs to address the problem of switching between the two interfaces that collided in Windows 8—the mobile environment formerly called Metro and the classic desktop interface—especially on 2-in-1 devices. For example, if you have a Surface Pro 3 and unplug the keyboard, should Windows still work the same way? A feature called Continuum, not available in the Technical Preview, will introduce tablet and keyboard modes that react on the fly depending on the hardware you're using. So we won't know for a while how well it works.
