Example 1: A simple link to an external URL: http://www.youtube.com/watch?list=PL1B4A81B7772380FD&feature=player_detailpage&v=_0dDn7mLTX4
1. click on the video with the right mouse button. Video properties window appears.
2. You have 4 possibilities here to copy a video URL:
Here you can see "copy video-URL" for Example 1