Leanback plays the videos based on your feeds and recommendations and it's controlled entirely with a keyboard's arrow and enter keys. Pressing up or down displays a search bar, lets you browse various content categories, and also gives access to basic video controls. The remaining buttons let you navigate or select items – nothing fancy, but it's all you really need.
For now, Leanback has been added to the growing list of features on TestTube. You can try it out by visiting youtube.com/leanback. In other company news, YouTube has also launched a new site for mobile users (m.youtube.com), with features including a more touch-friendly interface as well as more functions from the main site such as favorites and ratings. You can watch a video detailing that here.