[La Grand Orange] is a little L-shaped strip shopping center in Pheonix, Arizona. Really all the did is give it a fresh coat of bright paint, a gourmet grocery and they put a restaurant in the old post office. Never under estimate the power of food to turn a place around and make it a destination... [I]t provided its neighbourhood with what sociologists like call a “third place.” If home is the first place and work is the second place, the third place is where you go to hang out and build community.
Ellen Dunham-Jones gave a fantastic TEDx Atlanta talk on Retrofitting suburbia.
The idea of a “third place” appears to have been put forward originally by Ray Oldenburg in his book The Great Good Place. The Project for Public Spaces provides has some great quotes from Oldenburg on the subject.
Most needed are those ‘third places’ which lend a public balance to the increased privatization of home life. Third places are nothing more than informal public gathering places. The phrase ‘third places’ derives from considering our homes to be the ‘first’ places in our lives, and our work places the ‘second.’
The character of a third place is determined most of all by its regular clientele and is marked by a playful mood, which contrasts with people’s more serious involvement in other spheres. Though a radically different kind of setting for a home, the third place is remarkably similar to a good home in the psychological comfort and support that it extends…They are the heart of a community’s social vitality, the grassroots of democracy, but sadly, they constitute a diminishing aspect of the American social landscape.
Once again, I'm going to tie this to Steven Johnson's recent work. His coffeehouses and salons are decidedly third places. I'm not sure if facebook or twitter are actually third places, but in today's London, the various geek meetups serve the function of a third place.