Imageboards have always been a spectator sport for the most part for me although I remember one time making a thread on /b/ about something actually legitimately serious, and it kind of took off. It was pretty amazing, but I never really took the initiative a lot there, or when I did, it went down the memory hole, perhaps because I tend to be long-winded/tldr. Having your interactions mean something and getting interaction back (either serious or troll) is important to me, so I'd have to go with old school forums, but the politics and drama are vicious and personal and can play out for years.I'm sure there's heavy politicking in imageboards too in fact we all know there was for 4chan and 8chan, but it's out of sight and not a painful fact of everyday forum life. Until it isn't, and some board gets pulled, or a bunch of people get banned, or whatever. And there's also weird meme-forcing politicking by autistic gangs of faggots who plan faggoty ops. The highly personal shit isn't there, unless I guess you are pretty high up in the food chain. But both are horrible, and yet the best we have available.
Other shit: Reddit's audience base is so gay and their jokes so formulaic I just can't with them, although there are a few good Warhammer subreddits. Twitter used to be based for a hipster thing and is now possibly gayer than Reddit. Discussions on other social media don't even count in a discussion like this.
Kiwi Farms hosts some of the best "general" forums I've been on and Null does as good as anyone in creating a safe space to obviously discuss amusing lolcows but also discuss multiple interests in the various off-topic forums and balances reasonable moderation with putting the users mostly in the drivers seat. Moderation is pretty invisible and yet the forum has a good tier of discussion except when threads about politics get out of hand.