This concept is very intresting who are intrested in special efficets. This feature will make the background dark and enable the user viewing in a Theater.
Google Blogoscoped has unearthed a new YouTube feature that's pretty neat. Called "theater view," when clicked it both darkens the screen and increases the size of the player, centering it on the page and adding red curtains. For a leaned back viewing experience it's certainly not as useful as hitting the full-screen button, but I'd consider it a nice alternative--especially if you don't want to watch larger version of a grainy video just to cut out distracting page elements.
