Hello! In the updated version of the board rather than having a tag to specifically show a YouTube video there is a tag that is supposed to work for any media type. So far I know it works for YouTube. You can either type in your URL between two media tags [ media ] <your URL> [ /media ] (without the spaces) or paste a link, highlight it, and then click the little monitor icon at the top:
New Media Tag
Moderator: Moderators