Also being a "Pale Mooner" I have noticed that if I attempt to play a YouTube video it often either takes ages before it starts, or will fail completely. However if I hit F5 (refresh) it plays straight away. If I use my "Portable" version of Firefox this strange behaviour doesn't happen. On other sites like Vimeo there doesn't seem to be a problem. Since many YT clips now use HTML5 I wonder if there is some conflict which is making PM try and handle a clip with Flash when there is another format available?