Website full of trolls, losers and low lives. The comments section on most of the videos consists of pearls of wisdom along the lines of "ure gay", "ure a retard" or "i hope u die in a fire". Then when you disable comments you get messages telling you you're a coward. Disabling comments isn't cowardly, it's perfectly sensible not to want to read the inane comments that these utter morons leave.
Luckily there's now an option of only receiving messages from people on your friend list. If you're uploading your first video I suggest you disable comments and only allow people on your friend list to contact you.
YouTube users also seem to like viewing videos of bands they don't like just so they can whinge about something. Look at a Pink Floyd video for instance and you'll see dozens of comments saying things like "Pink Floyd suck." OK then, p*ss off and watch another video and stop complaining you idiot.
Inside the mind of a typical YouTube user - "I hate your videos. I hate them so much I watched them all just so I could post moronic comments on all of them. I could have watched videos I actually like but I'm too much of a loser to do that. I'm also too much of a loser to make my own videos but I feel it's perfectly acceptable to criticise other peoples work. If you block me I'll make another five Id's just to harass you. I have all day to spend on my school computer making an idiot of myself. I have to do something to take my mind off the fact that I'm an insignificant prepubescent little child"