Trolling used to be more prank-ish but it would already at that time certainly devolve to doxxing and start affecting people's real lives. I remember it took me a long time to stop caring on not leaving traces that people could link to my real name, my real pictures or whatever online.
I remember people on online forums salivating when Google came out and was a much better search tool to link an username to an email and from there to your life outside the internet. It was scary to post something confronting these trolls because they could try to find you, they had enough free time for that.
So I don't know when the internet was really that naive and innocent place, it had more innocence but this bad side of it was very present from the get go, at least in my experience.