I Have a Dream, and It's All About Cortana
This is where I want Windows, Xbox, and Cortana to be like in the future. I thought about this about two weeks ago before Apple announced their Continuity feature; I mention that because the ideas are somewhat similar, as it too pertains to device presence and their awareness of others.
I have an Xbox with Kinect, along with a Windows 8 tablet and phone. They're on the same network and linked to my Microsoft account, which gives them access to my speech and user data. Using sensors like Bluetooth so the devices are aware of each others presence and Cortana always-listening opens up many awesome possibilities.
Imagine being able to simply say "Cortana" and all your devices around you start listening, even wearables like a smartwatches. Since they have access to your speech data, only your devices (or the ones you're signed in to) start listening, so if you live in a multi-person households or have guests over, the requests are handled appropriately. Let's say I came into your room and shouted "Cortana", nothing would happen, except my phone starts listening. But if I signed in to your Xbox or Windows device, then shouted it, my phone and that device would now respond to my voice. I can then say, "Play (song/movie/TV show episode) on (whatever the device's name is)." and it starts playing from my collection. With WiFi Sense, Microsoft has already made it easy to get onto friends and families WiFi networks, so once your on the them you can tell Cortana to sign you into other devices that are on the it, like an Xbox. Also, with more devices around the room listening, they can be used together to better hear commands.
It could even work in situations where there is no internet connection. Even when offline your devices can contain your user and speech data locally. They can make it possible for you to be able to can sign-in to a nearby device with NFC, Bluetooth, or WiFi Direct and that information can be shared to it. Then you can tell Cortana to play things that are locally available on your devices. No need to identify which device has the content on it, she will know and play it to the device you specified by name.
For gamers, you could plug-in your external drive into a friends Xbox, tell Cortana on one of your devices to sign-in to it by its name (it's already broadcasting a WiFi signal), and immediately start playing your games and even continue progress with your game data cached on your devices and syncing back up to Xbox Live when you get online again.
What do you guys think?