Obviously Twitter could be helping a little bit, who knows how bad it would have gotten if Twitter didn’t exist (for background, Twitter is _huge_ in japan, and seems to be slowing down the lack-of-contact social problems).
I really think that getting people together in person as well as online is mega important. Brightkite is already starting the process, and people need to stop joining just to act twittery, and start using it to say “hey! we both use brightkite! we must be into similar things!” (brightkite actually lets users tag themselves, but that’s a bit awkward)