You can now add videos in comments and in adoption and shelter listings. It's easy, all you have to do is post a link (not embed code)-- the URL will be converted and automatically appear as a video. This will work for videos hosted at Youtube as well as Vimeo.
Please note! For Youtube, you must use the "long link" that looks like http://www.youtube.com/... , not the short link that starts with http://youtu.be/...
Here's a demo using a little video from Daejeon back in 2006 :)