If you are savy enough to copy the embedded video, then click on the <S> button in the white editing portion of the editing band that shows up on top when you attempt to add a reply to this forum thread.  Paste your "embed" copied code and then enter. 

Some youtube video posters don't let you embed their videos so the videos can be posted like this:  Simply post the address from the address bar. And use this if all else fails on the embedding. 

Paste the internet address in the body of your reply and it will show up like this one below. 

http://www.youtube.com/watch?v=8LqGlFv9woo&feature=fvsr

Then when you view these links, just click on OPEN THIS CONTENT IN A NEW WINDOW AND IT WILL WILL WILL WORK AFTER THAT.