A nice post drawing analogies between physical and digital spaces: An Elite Is Inevitable?: "As I think about building an online space which recognizes the value of proximity and unintentional contact, it seems like a technical infrastructure which forces space to be a finite, limited resource with transferable control has the potential to increase the value for people in that space."

...though of course, I'm not sure why it matters that online spaces "tend to become sprawling ghost towns", or why reuse of land matters when this sprawl is entirely virtual. Viva la sprawl!