Comment by 9point6

The exact example you're describing is what the ActivityPub spec and the resulting "Fediverse" are aiming to solve. Mastodon and compatible microblogging platforms are distributed versions of Twitter, Lemmy & Kbin are compatible distributed versions of Reddit/HN style link aggregators.

Given the boost both of these parts of the fediverse have gotten from Twitter/Reddit's series of missteps recently, they're starting to look like they could become viable long-term alternatives.