There was a genteel, supportive quality of having a participation base comprised mostly of sincere, interested readers and posters. There were trolls even then, for sure, but they were few and were generally embarrassed into an inert mumbling.

I still remember fondly the debates in comp.lang.c about the first ANSI C standard proposals. Even Henry Spencer's rants against NOALIAS were entertaining.

And where user participation got unproductively unruly, moderated groups served well, like rec.humor.funny.

There was also an open, transparent process for forking groups, generally along natural fracture lines, and for creating new subgroups.

What ultimately ruined Usenet (IMHO) was a falling signal-to-noise ratio, and not just because of spam. The opening of the AOL gateway and the resulting Eternal September proved to be mortal wounds.