It appears there are some Xbox One consoles out in the wild. The Verge's Tom Warren appears to have gotten his hands on one, and promptly started to test the console's multitasking ability through Snap. With Snap, you'll be able to pin various apps to the side of the TV screen, all while your game is running. Unfortunately, without being signed into Xbox Live, much of the functionality is disabled, but this video does a good job of showing how Xbox One excels at running multiple programs at once.
Also not used in this video: Kinect voice recognition. Warren seems content on using his controller for Snap features, but you should also be able to use voice commands to do things like "Xbox, Snap Internet Explorer."