These are the steps you need to follow in order to post youtube video: 1) Click the video of your choice. On the right side of the video there is a box within which you will find a text-area labelled as 'Embed'. 2) Click inside that Embed text area. The contents within it will be highlighted. 3) Copy the highlighted area and paste it in the Message box from where you post your message. And that's about it. Good luck :)