In the create a new post, or in the advanced reply section (not in the quick reply), you now have the ability to embed youtube videos.
This will be a great feature to share videos and not be forced to leave the site.
To post youtube videos, you need to just post the "code" and not the entire link.
For example in this video:
To post that link into an embedable one, you take just the "-EVqT3XEzss"
and put only that into the code [ youtube ] -EVqT3XEzss [/ youtube ]
And it will show up correctly. Enjoy!