Well, there's nothing new with the forum per se, we just upgraded it to a slightly newer version (Think Windows 8 to 8.1, nothing major), and we are using a temporary layout, since the old one was accidentally overwritten by the upgrade.
I always thought we had youtube videos enabled. After doing a quick check though it appears that the support for it was disabled. I don't know if it was the forum upgrade that disabled it, (or there was abuse with that feature in the past, I do remember something like this occurring) but we've always had that feature available. I have re-enabled it and it should be working fine.