It seems like Youtube is not stopping yet after they switched to widescreen format last week. They’ve just switched now to HD!
This new feature in YouTube allows its users to view contents in High Definition format. Users will be able to watch the video in HD by clicking on the “watch in HD” link at the bottom right side of the video where the “watch in high HD” option usually appears.
Files that are not in HD format are not viewable and users won’t be seing the “watch in hd” button.
There are some HD videos right now playing in YouTube. Just try searching “HD” on the search engine in YouTube and you’ll be able to pull up videos that has “watch in HD” tag. Please be aware as well that you need to have a very fast connection as HD files consumes much more bitrate files than that of a normal files.