Remember those days when you could have a guestbook on your website without any kind of filtering or protection whatsoever?
@deshipu there were category directories, then (yahoo.com was one of the early ones); you could find pages that were just lists of links to people. And we linked to each other, so if you found one of us you could find more.
Also I posted to usenet; it was a trivial thing to look at my email address & construct the url for my personal page, even before I started listing my url in my signature.
Even twenty years ago there were people trolling the internet looking for targets to abuse; they found us the same ways we found each other.