

Neat. But it’s not pre social media. Social media has been around since the 1980s.
That’s why I alternately call it the “platform web” in which social media stopped running on open and interoperable protocols and started being walled gardens on commercial platforms.
And to your other point - it shouldn’t be solely up to forum admins to opt-in to the Fediverse, end users should be able to subscribe to the forums they belong to with Fedi-powered tools.
The Fediverse could and should be the place where all those things can converge but I’m pointing out that it currently is failing to be that.

Services like eBay are part platform, part people. eBay’s people do a lot behind the scenes to ensure it runs smoothly and ethically… AND they take a significant chunk of the proceeds. You could put up some free software that does auctions but you wouldn’t have all those high paid security and trust workers working for you.