I'm 30, so myspace and Facebook showed up only once I was in high school, but everything you describe was still available on the web before social media. Shock sites were huge (goatse, tubgirl, etc), and I remember watching a beheading with a chainsaw by a Mexican cartel. And of course porn was around too.
The difference with social media is the "keeping up with the Joneses" except now it's your entire life, not just your literal neighbor. Way more damaging long term, since you actually know these people and can relate to them. Yeah the beheading was shocking, but I'm not hanging out with cartels regularly. Just a completely different thing.