OK, let's spitball. Maybe too much for an HN comment, but here we go:
- Define an open protocol
- There are multiple viewers (browser plug-ins), so different users can choose a different viewing/comment ranking interface experience
- There are multiple "channels" of comments for any piece of content, but usually channels will be topic-wide, sitewide, or even internet-wide. All content for a channel comes from a single server. If channels were pulling from existing sites, an episode of TV might have a channel of Reddit comments, a channel of Vulture comments, a channel of AV Club comments, and anyone can create a channel. (Maybe Reddit and Vulture don't participate at all)
- The person/group who runs a channel does/delegates all of the moderation for that channel. They do this out of the good of their hearts, much like Reddit moderators
- Each plug-in gives you a default, or a choice of, approved/blocked channel lists according to your political/cultural/etc. preferences. These lists are maintained similar to adblock lists, each of which are curated by groups with those preferences. So you can avoid unmoderated toxic channels or view them exclusively
- And so each viewer will combine all of the comments from all approved channels into a single comment list. Each top-level comment can come from a different channel, but all subcomments always belong to that same channel. When you leave a top comment, you can choose which channel to leave it in (or have it default to whichever channel is most popular, similar to picking the most popular subreddit on a certain topic)
- User accounts are managed by separate servers, but user servers don't hold comments/upvotes/etc. They merely provide signing to prove comments came from the same user, index comments left by that user, sum the user's received votes (which can be independently verified by the channels), etc. These servers are similarly moderated to kick out abusive users. Channels don't allow comments from users from user servers that don't kick out abusive users. Ultimately your identity is proved by a private key you can always take to a new server. Probably, the groups behind the most popular channels and/or most popular lists will provide these user servers as well
Whaddaya think?