I sat on the L train yesterday reading an article in Scientific American about the evolution of subway networks, since I cross under the East River daily, I read on. While no two subway systems are very much alike in today’s mega cities, there are universal elements that can be identified across all systems. And this interests me when thinking about networks in general.
The details of a city – its landscape, population densities, convergence with other transport systems – all cause the shape of the system to change dramatically. If you take the essential components of the network, you’re left with a few common elements of an efficient network:
“…the rules are universal, but are adapted to different environments… If the rules are correct, then simulating the growth of a network around a lake will produce a network similar to Chicago’s.”
If you have the rules, and plug in the variables of a given city, you should get an approximation of the subway system they have.
This is a cool idea when applied to social networks. If you figure out the variables of a given network: instagram has to be mobile, Path you only share with your closest friends, Facebook’s loosely associated friend base. It could be the same as identifying that Chicago has a lake you need to dig around.
If you could plug in these variables and find the most efficient model for growing a social network, that would be a very useful model to have. You could create a much more robust network. You could grow it extremely quickly by targeting the right “hub” people. You could use your marketing budget in a more efficient way by avoiding hitting the same groups of people repeatedly with your message.
The research concluded by saying:
“Understanding how subway networks grow and evolve might one day help to design better systems.”
I think we have a long way to go in terms of improving current social platforms and enriching our social networks. maybe we don’t know what that will look like yet, but if we’re on track to isolating the factors that make a successful network, that’s a huge step.

