It's easy enough to embed a YouTube video. You simply put the YT code in the YOUTUBE tags, like this:
But when you attempt to link text with the entire URL of the video (that is, you don't want to embed the video, just to link to it, it embeds instead. Here is an example of text linked to a YouTube video:
[ame="http://www.youtube.com/watch?v=5N4XxB1jkZY"]Text to be linked.[/ame]
This appears correctly on preview, but not when the comment is submitted.