In practice I don't think this really changes anything at least for moderation. It takes a bunch of time and effort to moderate online communities - under the process outlined by the post you linked most communities are going to have a single effective clientside moderation list you can subscribe to anyway.
Totally unmoderated internet communities would be completely unusable because of spam, and it's also questionable whether you could even stay up with no serverside moderation - you'd have to delete stuff otherwise it just takes one script kiddie with a botnet to flood your disk space with garbage.
(User produced ranking/filtering algos though I can see being viable)
Parent isn't saying "totally unmoderated" he's saying the client chooses the algorithm/filters.
That means there can be a bunch of algorithms/filters out there to choose from (any tech savvy person could make their own as a blend of others that exist) and the end user could basically choose which feed[s] to subscribe to.
There are multiple providers of Adblock lists. It would be like that, not single-provider.
Regarding banning server-side moderation, we probably can't do it without decentralizing content delivery in a BitTorrent fashion. But even half measures like replacing moderators with client-side filters would be a big improvement.
Totally unmoderated internet communities would be completely unusable because of spam, and it's also questionable whether you could even stay up with no serverside moderation - you'd have to delete stuff otherwise it just takes one script kiddie with a botnet to flood your disk space with garbage.
(User produced ranking/filtering algos though I can see being viable)