What is YTINSTANT - Youtube Instant, as you type , you start seeing results of your searches.
Just like Google instant, "Google Instant is a new search enhancement that shows results as you type" Source
Note, here Google instant are for specific countries not globally available right now BUT youtube instant is, which is incredible. And the person who made the website got 2 million hits on his site within 10 days, which is pretty pretty awesome. His name and other details are, ( copied from his site )
Created by Feross Aboukhadijeh.
Read the YouTube Instant story.
Whoa! 1 million visitors in 10 days!
and add to this, he has been hired by YouTube itself (Ok! I'm not sure about the hiring but you can read the story of YTinstant been created in 3 hours here is the complete link: http://www.feross.org/youtube-instant-media-frenzy/)