Hey do know how to post the video itself, instead of just a link? I would have made the video viewable from this page (example: landon's watch thread), but I'm not sure how.
I had to try this too, so I used a video we all have seen but never get tired of watching.
INSTRUCTIONS
1. Find your youtube video.
2. On the right hand side of the page, you'll see an option to "embed". Click the gear next to embed, then unckeck "include related videos".
3. Copy the text in the embed block.
4. Back here to the board - when you post a message, you'll have the option on the menu bar of "wrap Youtube tags around select text (looks like a youtube icon).
5. You can do this one of two ways: click the youtube icon in the menu bar, then copy your text inbetween the brackets, or paste your text first, then select the whole text and then click the youtube icon.
6. Add text as desired, but that's essentially it.
Let me know if you're still having trouble or my instructions were too ambiguous.