I’m fairly new to fediverse/instances, but my understanding that these Instances are federated with each other, so they can show the same posts/communities (depending on their respective filters).
So, why does searching for communities show different results, and even show different subscriber counts for one that do appear across all results?
Is this a case of the servers just needing to sync with each other?
That’s intentional. You only see subscribers in your local instance. You might be the only subscriber - if there are no subscribers then the community won’t be loaded in your instance, that doesn’t happen until a user subscribes.
The bigger issue is that every post and every comment is given a unique number based on the instance it’s in. It gets multiple numbers, one for every instance that’s federated with that comment. However there is no easy way of moving between comments and threads to the same on any other instance (except for the host instance). This makes it very hard to reply to a comment on someone else’s instance with your own accont in another instance - you have to log into your account, then find the comment on your instance. You can’t guess the link, you have to go to the community, find the post manually, then find the comment manually.
Posts and comments should just be assigned one number, the number of the user’s home instance. Then every other instance could just use that number with an instance tag, like with communities and users, eg
https://myinstance/post/1234567@theirinstanceYou can search for a post or comment using the full URL from the other instance.
But yeah, posts and coments should be assigned GUIDs. This was probably avoided because your local instance creates the post before it is federated the the home instance of the community. There are probably some technical challenges but I can’t imagine they are insurmountable.
As an example, you could say the instance with the person creating the post should assign the GUID, but then you could have bad actor instances assign already used GUIDs to intentionally cause things to break. You could say the communities home instance should assign it, but what ID does it get between when you post it and when it’s federated to the communities home instance (it doesn’t go straight away, but is queued for background federation - which isn’t always successful)?
These are things that will likely have solutions, but it’s easy to see how the current setup came to be. It’s mich easier to manage from a technical perspective.