Yes, it is fractured, and that is by intention. The point is that no one single person can control the entirety of the Lemmyverse. Suppose a spez comes along and tries to ruin things. Then, at worst, he can only destroy 1 instance. Even if he destroys the biggest instance, then it’s a big loss, but it’s not the end of the entire platform. Lemmyverse lives on.

As for how the fracturing affects the user - not much. As mentioned in other comments, each instance can communicate seamlessly between each other. I can post to other instances, and other instances can post to mine. All information is shared.

One caveat, though, is that the Lemmyverse is still very much in its early growth stages. So you’ll find a bunch of communities spread out over a bunch of instances that do virtually the same thing. It’ll look like the community is fractured. But over time, users are probably just going to settle on a single community, we just don’t know which one yet. Think of it like subreddits on Reddit. There’s basically always 3 subreddits about the same topic, but there’s always the one major subreddit, which is usually the one that you’re looking for. We haven’t reached that point yet - we’re still waiting to see which is going to be the “major” community for most topics.

Yes, but technically no. The full name includes the instance, for example iOS@example.instance.

Similarly, you had multiple subreddits dedicated to a single topic, with slight variations in their name.

I recommend to subscribe to anything which seems interesting (including duplicates), then unsubscribing from annoying stuff.