Our leader provided us quite a while ago, to make youtube video links display inline. since we have several new members, here is the correct way to post a youtube video.
start with the following link to a KC video.
https://www.youtube.com/watch?v=aB_y09_uX_U
now what you need, is just the video id number aB_y09_uX_U
when you post this link, here is the correct parameters.
[xxxxxxx]aB_y09_uX_U[/xxxxxxx] where xxxxxxx = youtube
then you get this...