If social media are driven primarily by their ability to facilitate social contact, then we should be moving in the direction of an open social format.
My students like Twitter (speed), Facebook (friends), Myspace (fandom), Digg & Make (interests), Twine and blogging (sharing created content.) Not to mention Geo-location.
I don't see why we couldn't start with a desktop app like Adium to mash it in some way and then move to a cloud app. Then we will be able to see over the walls. Wish list: A sliding indicator for geo-location going from "exactly here" to "nowhere" would be nice.
The move would be invisible to your friends who prefer to stay in a particular comfort zone, yet visible to friends who are shall we say, more adventurous.
It's the heritage of Atlantic City, Las Vegas, and Orlando. The concept of the destination resort with an escape hatch.
Quite a few years ago, a retired judge from Atlantic City gave a talk about the way the city had changed in the wake of casinos. I believe he was trying to warn us that promises of increased tourism from gambling resorts were not reliable. The casinos had captured their tourists and were definitely not sharing them with the rest of the city.