There are now videos on Youtube that can be watched in a better quality. All you have to do is to simply add &fmt=18 to the end of the url of the Youtube video.

For example the original url is:
http://youtube.com/watch?v=W-jEc5UA_Ew

You just have to add &fmt=18 at the end of the url into this:
http://youtube.com/watch?v=W-jEc5UA_Ew&fmt=18

If the video supports this option, you’ll be able to watch it in a higher quality, if not you’ll just watch it in the usual quality setting. That’s all! Simple as that.

Not really convinced of this when I came across it earlier, I did a little test on one of the featured videos on Youtube. Check out the difference:

Original quality:
Youtube original quality

Higher quality:
youtube higher quality 

Now there really is a significant difference in the image quality. Finally a small reprieve for Youtube fans. Have fun doing so!

via Wired How-To