Yesterday Youtube rolled out an all new look and feel for a handful of selected users. The new theme for the site is cross platform so you will see it on both browser and Android. The theme makes the actual content the main focus so you pretty much get a screen of videos without all the other distractions. Google is also now using a faster framework called Polymer. This will allow them to develop even more features faster in the future. One other big advantage Polymer brings is a new black background. This looks great with the new layout. You can try out the new layout now at the link below.
via youtube.com/new