I keep mentioning I was like one of the first 6,000 users of Facebook when it first spread to the Ivy League and a thing to remember is it was originally sorted into distinct communities by campus (first colleges in order of prestige basically, then high schools). So effectively everyone on the network from your perspective was someone you might physically see that day.

“Relationship status” used to be like the killer app, updated regularly cause the users were young, yes, but also because the network was “social” in that it encompassed the set of people who might plausibly become personally significant in your physical life.