I actually think having large, centralized platforms actually makes the polarization problem worse because they encourage usage habits that keep people only wit

I actually think having large, centralized platforms actually makes the polarization problem worse because they encourage usage habits that keep people only within the milieu they've had curated for them within that platform. A more confederated system, like having multiple independent fora, means most people can dabble in and out of multiple different communities at once and not have their perspective on how the world is skewed in the same sort of systematic way. Sure some people will go down the rabbit hole anyway, but then they will limit their reach by virtue of being too extreme to appeal to "normal" or moderate people who don't think about this stuff too deeply and are put off by extremism reflexively. When things are more centralized, there's sort of a one-way ratcheting effect where you get exposed to mild versions of the thing enough to start getting into it, and then slowly get pulled into more and more extreme versions. That doesn't happen with forums that each have their own culture and identity, there isn't as much transitional/interstitial space to acclimatize you. You just jump in, read the vibe without being preconditioned, and make your instinctual call on whether you'd like to stay.