Follow these steps to embed a YouTube video into your forum post:
1. Find the video you want to share on YouTube, then click the "Share" button underneath the video:
2. Click the "Embed" tab:
3. Copy the link to the video (you only need the bit that's between the src="xxxx"):
4. Paste the link into your forum post, highlight it and click the YouTube button above:
5. Finish your post, submit it and you're done! The video will show up in your post, exactly in the same way a photo would.