+1 @whart
The reason I joined was to ask hobbyists about things that they would know but others wouldn't -- typically technical questions about all things audio. I've gotten a lot of great answers here, and a number of threads I've started have had long and involved discussions delving into the parameters of different questions. Other threads have done this, too.
One amazing thread I remember had to do with my discovery that my to-be audio room had reversed polarity on the outlets. Several very knowledgeable folks here (almarg, RIP) had me checking outlets with a multimeter, reporting back, etc. and they helped me troubleshoot and solve that situation. A perfect use for a hobbyist forum. Another thread was about setting up my room, short-wall vs. long-wall. Again, the exchanges were iterative and constructive, and the hobbyists on the thread were drawing on long experience and relaying it to me,
Threads that focus on specific brands are more likely to devolve into chest-beating contests and get nasty. Or, threads that involve people describing what something sounds like -- but without much control over variables necessary to figure out why things sound that way.