After watching early footage of Microsoft's virtual assistant Cortana in Windows 10 (below), its impending takeover of the Microsoft Borg seems inevitable. There's a lot riding on Cortana, after all. After being released in the U.S. earlier this year, it's now slowly rolling out across the globe. While an obvious response to Apple's Siri, Microsoft's devotion to Cortana is also a reminder of just how important these virtual assistants are becoming. It's as if Siri, Google Now, and Cortana will end up personifying the operating system wars.

http://www.engadget.com/2014/12/05/cortana-windows-10/