YouTube Embraces HD
What kind of HD format is subject to speculation. While YouTube's high-def videos are nominally 1080i or 720p, the data rates must be compatible with the user's broadband connection for the whole thing to work. And broadband speeds in the U.S. lag those in most other developed countries. So if YouTube insisted on videophile-caliber picture quality, it might leave a lot of its users behind.
YouTube is therefore checking out the broadband connections of its users to get a better idea of how to balance video streaming quality and bandwidth limitations.