There is a smuttiness prevalent on youtube that ultimately has made it off-limits to my kids. Example: a friend forwarded a funny Christmas video showing costumed monks presenting the "Hallelujah Chorus," silently using signs. As soon as it was finished, up come the suggested videos, one of which is entitled "the 12 gays of Christmas." I didn't watch that one - maybe it was funny too - but I surely didn't care to explain to by children age 8, 6 and 3 what the title might mean. So even when I'm in territory on youtube that seems kid safe, it seems somewhere on the page there something about (actual examples again) "how to shoot up heroin" or something about oral sex techniques.
I have posted several videos to youtube and been disappointed and often shocked at the abusive, sexual language left as comments, even though the videos were of my small children and were posted simply for their grandparents to see. (We're not posting any family videos to youtube any longer.) There seems to be a poisonous misanthropy among youtube users - or at least among commenters - that to me is starting to feel like the lingua franca of the web in general. Based on experience in the last year I'm starting to find the web an unsafe place for kids overall.
Maybe these problems will be addressed by the new safety feature. It will be hard to convince me, though. With the exception of text content, it seems to me that safety features will rely on user-provided tags and flags. As I have said, I don't have a lot of faith in youtube users as advocates for children.
As for quality, it's a phenomenal challenge to find content of genuine merit. Flippant fun is what we find primarily.
All this was a lot more fun before we had children. Now comes responsibility... sigh.