I'm not really sure what kind of conversation you're attempting to spark here. If you're thread is about not revealing personal information... well than that can be said not only about youtube, but any site you visit on the net.
As for these strange comments... I am curious... Were these comments placed under "random" videos? Or were you actually watching videos about 9/11, and UFO's ect.?
Anyway don't be spooked by the strange and adverse opinions of others. They may know something you don't. Or believe something you don't. Thats ok.... right?