I blocked YouTube on the Ipad. I was a little worried my kid might see some stuff on YouTube not intended for a 5 year old. My 5 year old found a work-around by starting up Angry Birds, clicking on the Angry Birds Cartoons, then browsing to his favorite YouTuber using the Voice Search function.
I have to say, that's brighter than most adults I've seen. He dealt with bypassing Password protection and his own inability to write using the speech function. That's amazing!