This is a hack of YouTube Video ID calculation system. Google used to maintain a single doc_id for all of their contents. For example, they are displaying a different video ID for each video url from youtube. But at background they are reverse calculating the youtube id, and convert it into google doc_id. Based on the doc id, they display content at youtube.

They tool is placed here, is just a complete hack of the revers ID calculating system of Google or youtube, whatever you say. If you enter a youtube video URL inside the below text box, it will return you the google video URL after reverse calculating the youtube ID system. And you'll see the doc id formatted google video url

Similarly, if you enter a google video url inside the text box, it will return you the corresponding YouTube video url using the same reverse calculation method.

Enter Youtube or Google Video URL, for example

http://www.youtube.com/watch?v=h0GA73O_9O4

http://video.google.com/videoplay?docid=-8700531239175588626

How you'll get proof that the system is the hack of google ID calculation process? Are you interested to get a proof? It is simple. Just take a new YouTube video link from Recent Uploaded section of youtube. And paste the link here. You'll find that the generated google video link is not displaying the video. The reason is google takes time to adjust it for redirection. So save the link, and try to visit the video url after some times later. You'll find that it will redirect you to video page. Satisfied?

Do not try to run spider/crawler/bot on this system. You'll just get blocked instantly.