First of all, I hope that this is not a support question and that I am asking it in the wrong community. If it is, I'm sorry. If these questions have already been asked, feel free to refer to the thread.

One thing I still don't quite understand about Lemmy is how upvotes (for posts and comments) and the number of subscriptions per community are counted across all instances.

I have noticed, for example, that the number of subscriptions for specific communities (feddit.de) is significantly lower than here at lemmy.ml. Why are the subscriptions not added up across all instances so that the same number of subscribers is listed for each instance?

Are the upvotes for posts and comments consolidated across all instances or only taken into account in the respective instance? What happens if an instance is not accessible, are the upvotes then simply ignored, is the number of upvotes for a post then significantly lower?

Thank you for the clarification.