I recently responded to someone's note asking about "if such and such a kind of person is on Nostr". And I realized that my reply would (obviously) be unique to my perspective in the graph. And that discussion of "if something is on Nostr or not" is fatally flawed. 

Yes your "network" may mean different things in different contexts (like home LAN as you point out) but I thought it was pretty clear which context I meant.