For embedding video from youtube. An example: http://www.youtube.com/watch?v=ddO9idmax0o&NR=1
This is a video about twitter. Use the last id portion (ddO9idmax0o&NR=1j) like the below.

[[youtube(ddO9idmax0o&NR=1)]]

You see youtube video like the below.

youtube(ddO9idmax0o&NR=1)