For me, the awakening to the vileness of the internet, was the "Offended" page on Encyclopedia Drammatica. People who wanted to ruins other's time on forums in a raid would basically post it as if it were a rickroll of sorts, just a completepy harmless comment with a link. And then the page would have 3 innocuous image right before showing you horrifying gore and body horror. I'm quite sure some of the most awful stuff usually on these lists, like screenshots of the guy who mutilates his own scrotum, were in there.