> Any instance can connect to any other instance by design. That includes any of the communities (sub Reddits). Any community is available from any instance.
Which is both good and bad. Good because federation of course. But it also ends up fracturing the community. Say all the r/python people decide to move out from Reddit to Lemmy. They are probably going to go to different Lemmy instances each with their own c/python community. Yes you can follow any c/python from any instance but let's be honest, how many such c/python communities are you going to follow?
So if you join a general instance (like reddthat.com #selfplug) you can search in the communities and find any other community and subscribe to it.
browse.feddit.de is the current place that searches every fediverse instance, and indexes all the communities. So your can find any community, even if the instance has not federated yet