Before Facebook, if I lost someone's contact information, and drifted outside of their social circle for a long enough time, chances were I would never ever see or speak to that person again. Before Facebook, if people wanted to organize conversation and cooperation on an information technology platform, the options were to pay $X00-$X000 for a proprietary system, get lucky enough to know about mailing lists, have so…
There were like 20 years in between what you describe and Facebook's dominance.
Before Facebook there were thousands of thriving independent forums on wide varieties of topics. I spent large portions of my teenage years on them and got way more value out of them than I have out of any Facebook group.