Here is a tutorial to view youtube hidden/removed video tags or keywords after the recent update (August 2012) and It is really simple.
Now Follow these simple steps:
1.Select a Video
2.Right Click on the page
3.Click "View page source"
4. click CTRL+F
5. and type in KEYWORDS
6, then press Enter

then you should see the bar on the right with number. See in the number 8. And find the following word “ <meta name="keywords" content= “ in the left side. After this word you will find many words separated by comma .Yes these are the Tags list used in this video
Hope you find this tutorial helpful. If you are having any problems just comment or send me a message.