Any post and community could be accessed through a theoretically limitless amount of instances, which also means a theoretically limitless amount of URLs.
Will this hinder Lemmy from ever coming into the mainstream? If I type any topic in Google, I will get a reddit thread that deals with that. Can something like that ever happen for Lemmy?
What’s contained within an individual instance is whatever’s viewable from that instance, though, as remote content is mirrored locally. So, any early instance that is well federated and subscribed to a large number of remote communities should work well as a search target.
So site:lemmy.ml actually shouldn’t end up being too and of a query.