Question About Embedding Video To Posts

How do you do it?

I've posted YouTube videos to the board before, but they've always been in the form of links that you have to click on. But I've noticed that others are able to post similar videos where the actual video is embedded and all you have to do is click on the "play" icon to view it.

I suspect that it has to do with the YouTube button on the message screen, but that doesn't seem to work for me.

Thanks.