Ideally they would join any instance and follow the topics they're interested like they would subscribing to a subreddit, and the fact that content is spread ou

Ideally they would join any instance and follow the topics they're interested like they would subscribing to a subreddit, and the fact that content is spread out over several instances isn't something users need to worry about. The reality is that discovery is terrible right now and you can't browse a feed of all Tech/Music/Art threads from all federated instances. Hopefully this is being worked on.