Apologies: this is the back of an A3 postcard!
Perhaps you might find Quora interesting, although they’re diving deeper and deeper into the dark side. It’s full of artificial arguments and intentional conflict creation, but in amongst such childish marketing idiocy are some genuine thoughts and conversation.
The contemporary alternatives seem to me to be worthy but lacking in that essential thing, numbers of users (my impression of Mastodon). Some appear to have addressed this by becoming propeller–head central (my impression of Diaspora; I regret looking into it). CIX survived by going paywall. Boards.ie is still around.
IMHO, faceboot won because, at least for me, the service(s) I use are those my family, friends and contacts use; I had little choice but to follow them here. I use the slightly less dire linked in for similar reasons. My family, at least, have shifted to faceboot’s whatsapp now. I really regret the loss of the social web ecosystem, there was some great stuff about.
There are other ways to address the personal information theft (IMHO reflecting a failure in copyright law, in that you can’t copyright your personal information and/or life’s activities, even though I put far more time into creating that than I do in creating poetry). For example, I run faceboot in a VM (Virtual Machine) which I only use for faceboot. I’ve set up other VMs for other information theft sites. This way the sites can’t work out what else I’m doing, what else I’m interesting in, because they can’t see it.
Where I can, I tell browsers to prevent as much of the information theft as possible. I tell browsers to suppress ads, and refuse to visit sites that insist I disable that suppression. I avoid as much as possible Google Chrome, indeed any and all Google services & products, and if I do have to use it, well, it has its own VM. etc..
Obviously, the information thieves will still get information from and about me, so I poison the well with false information to create contradictions to, hopefully, mess up their connecting the dots code. For example, my date of birth appears to be April 1st in 1941, 1951, 1961, 1971 and even 2001, depending on where you look for it. I have lots and lots of middle names, it seems. My poisoning is thoroughly amateur compared to people who really know what they’re doing (like my spelling), but it seems to be enough, judging by the lack of adverts I get related to what I’m doing online.