This is one of those things that sounds simple and intuitive on paper (“just” take all these communities of the same name from disparate instances, smash them together so they all display on the same page) but once you start thinking about the details it becomes clear that it’d be a logistical nightmare and a clusterfuck to actually implement.

For a start, moderation would become diabolically complex.

• If multiple communities across instances are merged, each has its own moderators. Who can moderate which content? Everyone? Only the moderators for the instance in which the content originated?
• If it’s the former, what’s to stop a rogue moderator from a bad instance from merging their community and then deleting content/banning users who aren’t theirs?
• What happens if a user gets banned from one instance, but other instances have merged content in this community under which that user is not banned?
• Who decides what community and instancewide rules apply to the merged instance of that community, which will inherently include users from outside their instance?
• Who sets what the banner and sidebar look like, considering that nobody from any given instance can “own” the entire supercommunity?
• Etc.

I think the only way this could possibly work at present is if were client-side, i.e. you can create your own supercommunity by merging content into a single page on your own device, but purely for display and in a read-only fashion. This would not provide the implicit benefit I think you’re angling for, though, which would be solving the Fediverse fragmentation problem.

I’d proposed a potential solution.

I’ll paraphrase : Currently, every Lemmy instance (ie: Lemm.ee, Lemmy.world, etc) is an island. This is one of the strengths of Lemmy (Federation) as we don’t have to worry about information being restricted, censored, manipulated (ie: Reddit).

However, as things are currently, this Federation comes at the expense of splitting the community between instances. [email protected] vs [email protected] is a perfect example. Posts are either duplicated (which creates noise) or it fosters a “Lemmy instance death by starvation”. Meaning, more and more conversations will eventually drift towards one of the two asklemmy communities, leaving the other one to “starve out”. This defeats the entire purpose of federating.

There has to be something better.

For example, instead of “every instance is an island”. Meaning the current hierarchy is “instance” - > “community” - > “post” - > “threads”. We could instead have “community (ie: asklemmy)” - > “post (ie: this post)” - > “instance (Lemmy.ml, Lemmy.world, etc)” - > “threads (this comment)”.

From a technical perspective, it would mean that each instance (that’s interested in hosting this supercommunity) would replicate the community names and posts (Not the threads).

Lemmy already kind of does this, when a user pulls a post from another instance. For example, I’m on lemm.ee but when I view posts from [email protected], lemm.ee will retrieve and cache it on lemm.ee. As long as each instance would share a unique identifier to associate the two communities/posts as “the same thing” (and this could simply be the hash of the community /post name). Everything else would be UI.

Each instance would take ownership of the copy of the community and post, which means they could moderate it according to their standards.

As an end user, you’d view a community and post, but the comments/threads would be grouped by the instance that hosts it. If there’s an instance you don’t like, you simply unsubscribe from it.

For future iterations, it might be nice if the instance itself would auto-subscribe or suggest other instances that host the same community to the user. Meaning, if I subscribed to [email protected], I’d automatically be subscribed to [email protected]. However, as the user, these are all separate subscriptions, so I can customize it as I see fit.

To respond to questions about implementation, I was thinking something along the lines of communities are federated with each other.

Some workflows:
Posting
I want to make a post to c/tech, so I post on [email protected], my post then gets federated to the other instance and shows up there. (Servers would want to add de-duping for people who are subbed to both)

Deleting my post
Similar to above, it gets marked as deleted on both

Mod action:
Mod on lemm.ee removes my post, the event and reason get federated. The other instance could be set up to follow the action or have a mod action to do anything with it.

But anyway, for now I’ll try to see if there’s a way to group communities, but I don’t think Sync for lemmy has that.

The reason I was thinking this is because this part of federation actually makes things harder. And then there’s the aspect of “where do you post this”, bc sometimes the community is bigger on another instance, so you cross post just because it’s essentially the same thing, just somewhere else.

To OP and any smart coders out there: if you could implement this feature into Lemmy yourself, you could earn up to a cool €6000.

Seems to me all you have to do is possess and lock all but one community with a link to the main one. That resolves all the comment and federation issues.