When I was 12 (so, 2007), I actually operated a massive list of shock sites on a now-defunct site called BluWiki.
Once upon a time, in ye olden days of the internet - before even 4chan - the most influential sites for internet culture and memes (along with the main hubs for trolling) were Something Awful, Fark, Newgrounds, and Slashdot. Slashdot had such a huge problem with trolls - especially with trolls tricking people into clicking hyperlinks to shock sites - that they had to implement a new measure whereby any hyperlink would automatically display the URL of the site that it was linking to, making it much harder for trolls to sneak in links to Goatse, Tubgirl, Meatspin, Hai2u, Last Measure, and so forth. I think Something Awful, Fark, Newgrounds, and Slashdot are all technically still in operation, but hardly anyone actually goes there anymore. Shock sites have largely faded away as well. It's been years and years since trolls were tricking people into clicking on links to pictures of gaping assholes. Juvenile pranks like that (which is primarily what I was doing as a preteen on sites like YTMND and Gaia Online) used to be the driving force behind internet trolling, but today's internet trolls overwhelmingly tend to be much more extreme and usually have some far-right political ideology driving them, hence the emergence of the alt-right from the various fevered swamps of the internet. Back in the '90s and early '00s, however, it would have been downright unheard-of for an internet troll to be trolling on behalf of fascism; the internet counterculture had an overwhelmingly libertarian and generally left-libertarian leaning, with the internet essentially being treated like the wild west and viewed as a new frontier for freedom that normies hadn't yet ruined with their crippling laws and regulations. Honestly, I do miss the old days of the internet, when it was a much more niche thing that not everyone had. Internet culture was very different then, when the internet was largely dominated by nerds and outcasts and any attempt to change that was fought tooth-and-nail.