I have a suggestion for YouTube that I think would help it a TON! I'm sure a lot of YouTube surfers will agree.
So when you're viewing a video and the sidebar of "Suggestions" or "Related" videos come up, I suggest that below the Title, Length, Channel, and View Count for each video there should be a tiny "Likes/Dislikes" green/red bar. This way, at a glance, you can tell if a video may or may not be worth the watch/click!
I figure there likely won't be enough room for the actual likes and dislikes numbers to be squeezed in there, however a thin green/red bar will GREATLY help users sort out their next video watch!