Now youtube has a new design with some google+ integration and content discovery features. The new YouTube design is being rolled out in stages, and for those who haven’t yet received access to it, follow the below steps to enable it.
Open your browser’s development tools (only firefox and chrome)
In Firefox: Ctrl + Shift + K (Win) | Cmd + Shift + K (Mac)
In Chrome: Ctrl + Shift + J (Win) | or Cmd + Alt + J (Mac)
Then add below code to the console and hit enter.
close the browser development tool and reload the youtube page.