Personally I think what you do is more important than what you see.
I'm all for anything that gives parents a better/easier option to control what their child is exposed to but mostly it's pointless. Kids are crude, vulgar and nasty by default. When their young it's boogers and farts, then it becomes dirty jokes, stashes of adult magazines, and two girls and a cup style videos. And guess what, chances are they are experimenting with sex much earlier than you would think possible.
In my opinion the best thing you can do is be a good role model for your kids. A real world example is far more powerful than a you tube video. Show them healthy respectful relationships, mature conflict resolution, responsible alcohol use. If you want them to read more let them see you with a book in your hand. If you want them to take school seriously, let them see you exhibit a love of learning.
However it would be really appreciated if their is was a could friendly, curated you tube spin off. :)