Youtube is wonderful for the thing that it strives to eliminate, posted copyrighted content. Most of the original content, is not worth listening/watching in my opinion. It can be funny, but it's often a good way to waste an hour. I've found some of my favorite singers due to youtube. It's a lot of fun if you have fast internet and the time to waste.
A lot of the videos are stupid, just ignore those ones and dig for interesting and original content.
If you have good common sense, then youtube is a fine site. if you do open some vids, there is some malware, trojans and viruses. but as i said, common sense.