This is one of the biggest issues and barriers to discoverability with the Fediverse in my opinion.
As I understand it, unless an instance has already subscribed to a community (magazine in kbin parlance), then in order to make that community (magazine) appear in your own instance, you need to:
- First search for the community (including the community's home instance) name in the magazine search function.
- The search will come up blank, but the act of searching for it will trigger a backend request for your instance to start federating content from that community. However there's no message to tell you that it's doing that. It just looks like that community doesn't exist.
- Further, it may take up to several days (in my experience) for federation to start, ie, you have to repeat the search for the community and only then can you subscribe to (follow) that community
- And when it does start, it only starts grabbing new content. So first it looks like the community doesn't exist, then it takes a long time for content to appear, and then it looks like the community is sparsely populated unless you go back to the community's home instance, rather than staying in your own instance, to catch up on old content.
- Further pinned posts aren't federated (at least between lemmy and kbin I believe), so you can't even rely on a "here's what you need to know" introductory post to orient new members.
Contrast this to reddit, where (because it's a centralised system) searching for a subreddit produces immediate results, you can join a subreddit immediately, and you can immediately see all current and past content for that subreddit. Much more intuitive and useful to users.
Unfortunately the activitypub protocol that underlies lemmy and kbin doesn't appear to have been designed for reddit-like communities in mind. Ie communities that tend to feature long-form content, posted relatively sporadically, and where having access to the community's archive is very useful to members. It works somewhat better for twitter-like communities where it's easier to jump in "mid-stream" and - because posts tend to be only a few words long - you're more likely to start seeing new content after only a short delay.
I wish that this is something that's addressed at the Fediverse level.