I like the term coined by Leisa Reichelt, “ambient intimacy.” And coincidentally it’s exactly the experience you had of incidentally observing that people in your neighborhood were all on Facebook. Leisa’s blog post is here: http://www.disambiguity.com/ambient-intimacy/ but the idea is that there’s lots of information about our friends and relations and neighborhoods and “groups” we affiliate with that we pick up without seeking it out. Yet in modern society, with people living farther apart, the quality of our relationships is lessened when we have less “ambient intimacy.”

As I outlined in a blog post a couple of years ago, Facebook is a way to pick up more of that ambient intimacy from people you care about but who you don’t see everyday. My post is here: http://gravitationalpull.net/wp/?p=527