YouTube now has a new, refresh layout and according to Google, “in the new layout, the video display is cleaner and more prominent”. However, YouTube’s home page is now left-aligned and on wide-screen monitors, it results in lots of white space on the right of the screen. You can fix this white space annoyance by centering the YouTube page. Here is how it is.
You can fix the white space annoyance of YouTube’s new layout by installing a user scrip called “Youtube Center Aligned”. The script works on Firefox, Chrome, and Opera and can download from UserScripts.com.
Since Chrome supports Greasemonkey scripts natively, you can install user script without GM. To install, download the user script, and open the Chrome Extension page (Menu > Tools > Extensions) and drag-and-drop the downloaded script inside to install it.
After installing the user script, go to YouTube homage, click on the YouTube Center toggle icon (gear like icon, see screenshot) and check the box “Center Page”. [Via]