Social Networks and Urban Networks have definite similarities, at Nlab Roland Harwood from Britain's National Endowment for Science, Technology and the Arts (NESTA) introduced the topic and I'd like to expand it a bit here.
In essence, as people gather, the number of contexts in which they can gather increases. The number of people involved make long-tail groups workable.
These groups allow people to explore their individuality, oddly enough. You can experiment with, investigate, join, and remove yourself from the group. The larger the community, generally, the larger the choice and the lower the penalty for withdrawal.
Groups thus allow opportunities for growth in thought, economics, and innovation.
Previously, the idea was you had to go to a place and do a bit of living before you could join these groups. This required clustering and migration to places that represented the group you wished to join.
Mormons in Salt Lake City, film in Los Angeles, Chocolate in Brussels, International Finance in Hong Kong.
Thomas Friedman gave us the argument that the world is now flat - meaning that the Internet removes the requirement for physical proximity. With the Internet, I can now join communities on-line and no longer have to move to a place to be part of a scene.
The barriers to joining a community that discusses your topics are remarkably low now. However, there is no substitute for face to face interaction.
We are, at heart, social animals and face to face communication comes with a great deal of visual, physical and psychological cues that provide vital interactive information.
In addition, physical proximity throughout history has given rise to rapid innovation by providing immediate feedback to people within a community. Meetings in coffee houses have shown to be tremendous agents for change.
Therefore, even in this digital age, we still have our silicon valleys, our Sohos, and so forth. There is still a market for physical proximity - otherwise people wouldn't be paying $800,000 for a crackerbox house in the bay area in the middle of a housing bust. They'd be picking up great deals in Madison, Wisconsin.
But we also have great bits of innovation in Salt Lake, Omaha and Nashville.
Why? Because the Internet allows for the rapid distribution of innovation and that is important. The world is spiky because we are social and we want to see each other. That used to be required, now it is optional.
Both the Internet and Cities are networks, they are highly coordinate. They foster basic human needs and support human growth. As a species, the Internet will greatly impact our intellectual and social evolution.
The flow of information, the flow of traffic, and the flow of blood through are bodies all follow very similar basic laws. Movement with purpose, movement that provides nutrition, entropic systems.