Frequent and occasional users of Youtube.com would have noticed a big/wide change today when you tried viewing a video on their website.
Quote from their blog announcing the change:
We’re expanding the width of the page to 960 pixels to better reflect the quality of the videos you create and the screens that you use to watch them. This new, wider player is in a widescreen aspect ratio which we hope will provide you with a cleaner, more powerful viewing experience. And don’t worry, your 4:3 aspect ratio videos will play just fine in this new player.
Although this is has been a major change that would be welcome to some, it will no doubt be frowned upon by others. As this comes as default, videos that were not made for this widescreen resolution will suffer some noticeable quality loss, especially those that are in the old 4:3 resolution. Besides the quality loss, videos in 4:3 resolution will have black bars added around it to make it fit the now 16:9 resolution player. If only we could turn the widescreen off for 4:3 videos. Well, at least we can look forward to HD on Youtube.com now.