Virtually identical absolutely. But in my personal experience over the last few months, I see content that's in lemmy.world that's not on lemm.ee

For a while, because content was more thin, I'd run through all of active, then all of hot, then I'd look at lemmy.world just to see if there was content I hadn't seen yet

Almost definitely, it's hard to imagine there's a community on lemmy.world that not one of the 20k users have susbcribed to