I personally find youtube to be a great resource, and a terrible detriment to the magic community. I have seen my share of terrible videos there, but I've also learned some great effects from some equally great teachers. For example I learned Dia Vernon's Twisted Aces from an amazing teacher on youtube. I've also seen my share of the classic "kid revealing magic" videos. If there were more good magicians on youtube doing good tricks, it wouldn't be so bad. I just finished a summer-long job at a theme park doing magic for people and I never once heard the old "i saw that on youtube" but there were plenty of people willing to look it up later (luckily I never say the name of my effects). I also saw many people who bought magic kits or books that seemed ready to take on the challenge. I think it's a beautiful thing when someone is willing to take the challenge and learn magic, but I also think it's a terrible thing when people are looking for secrets on youtube that they'll never use. My verdict is that youtube is both a good thing and a bad thing. I also think it depends on what videos you see.