"A big downvote ratio will get most people's attention in a way that critical comments may not." I'm sorry but this is one of those things which absolutely needs citation. I can't remember the last time I looked at likes/dislikes to decide whether to watch a video. The thumbnails on the watch/rec page are what draw me in to watch a video, I don't bother looking at the number of likes/dislikes (or comments) until maybe after watching the video.