Data Center site selection is part art and science. There are many Facebook partners looking for peering relationships with Facebook data centers. 600 million users is an appealing number. A graphic shows the users in an interesting display.
Here is background on the data to create the graph.
After a few minutes of rendering, the new plot appeared, and I was a bit taken aback by what I saw. The blob had turned into a surprisingly detailed map of the world. Not only were continents visible, certain international borders were apparent as well. What really struck me, though, was knowing that the lines didn't represent coasts or rivers or political borders, but real human relationships. Each line might represent a friendship made while travelling, a family member abroad, or an old college friend pulled away by the various forces of life.
Later I replaced the lines with great circle arcs, which are the shortest routes between two points on the Earth. Because the Earth is a sphere, these are often not straight lines on the projection.
When I shared the image with others within Facebook, it resonated with many people. It's not just a pretty picture, it's a reaffirmation of the impact we have in connecting people, even across oceans and borders.
Think about all the data Facebook has for its site selection process. Europe and Asia look like obvious next places.
Note as GigaOm points out there are some dark spots in the Facebook network.
There are gaps in the data, of course, with dark spots in China and other countries that block the social network (or have large competitors of their own, as Russia does with VKontakte), but the result is quite an amazing picture of a connected world. If that’s what an intern at Facebook can come up with, imagine what else would be possible with that data.