Starting next week, YouTube’s HD mode will add support for viewing videos in 720p or 1080p, depending on the resolution of the original source, up from our maximum output of 720p today.

As resolution of consumer cameras increases, youtube want to make sure youtube is the best home on the web to showcase your content. For viewers with big monitors and a fast computer, try switching to 1080p to get the most out of the fullscreen experience. Just how much larger is 1080p? Take a look at the following screenshots from this video

Via youtube.blogspot