There're some changes to the format at YouTube official website...
So this is how we can link your youtube video to MercKaki:-
1. At the Youtube page where your video is, press the Share tab, you will see something like this:
http://youtu.be/0K-0vkFfUmY
2. Cut out only the highlighted in Blue:
http://youtu.be/0K-0vkFfUmY
3. Paste it into the following(after the '=' sign)
[youtube]http://www.youtube.com/watch?v=[/youtube]
[youtube]http://www.youtube.com/watch?v=0K-0vkFfUmY[/youtube]
Done(Sample Video):