• Microsoft's serious interest in the living room began when it acquired WebTV in 1997.
• My favorite of Microsoft's attempts to own the living room was released in the summer of 2002, Windows Media Center.
• According to Nielsen, the lion's share of TV on Xbox One is still viewed live.
• What the Xbox One will do is overlay Microsoft's OneGuide on top of live TV delivered from your provider's set-top box. It does this with its HDMI input / output and an IR output. You'll connect your provider's set-top box to the Xbox One via HDMI, then connect it to your TV. Finally, you'll attach the IR emitter to your provider's box. 
• The Xbox One does support HDMI-CEC, but despite my quiet pleas, this control protocol hasn't been implemented into a single one of the boxes that can access tons of premium content. 
• The reason for including CEC in the Xbox One is to control the TV and the AV receiver. Without it, walking into your house and saying "Xbox On" wouldn't turn those devices on.
• The way the Xbox One will take over input one on your TV is by offering all the most popular programming. According to Nielsen, live TV; Netflix; Blu-ray / DVD and, of course, games fill the screen for the majority of the time your TV is on.
• An enhanced program guide that brings together all the sources of content into one screen -- now that has potential.
• Add in some data from the internet in the form of socially curated shows, sports scores and additional information about what you're watching from sources like IMDb and Rotten Tomatoes, and things really begin to gel.
• The first box that came to mind when I learned of OneGuide was Google TV. 
• So, while the Apple TV has a fairly impressive iTunes ecosystem thing going, and the Roku has more channels (apps) than anyone, the Xbox One is the only device that is trying to do it all, premium live TV included.
• Sure, the Xbox One won't completely replace your provider's set-top box, nor the remote that came with it, but it does have the potential to change the way we consume content.

Full Article: http://www.engadget.com/2013/06/19/xbox-one-live-tv-microsoft-history-what-to-expect/

I recommend that you read the full article. Very good one if you are interested.

I will try this feature as soon as i get it.

Id' take the feature of being able to play Xbox One games on TV#1 while the gf/wife/kids watch cable TV in TV#2 (or viceversa) over this. Maybe it's possible to make some sort of complex setup to have both, but swapping discs is already too tiring for me, so this is light years away from my lazyness threshold.