Here are some great data visualizations from a Facebook intern in its data infrastructure engineering team, showing a map of social connections through Facebook. For the first time, a full map of the social graph. Paul Butler, had access to Facebook's Apache Hive database and its 500m records, and through a series of carefully constructed steps was able to create this. More details on how he did it here.
The images remind me of some of Aaron Koblin's work on flight patterns.
This work reconfirms the fact that the social graph follows economic, political, and cultural ties. The English speaking world links together (e.g. UK, and North America), Portugal and Spain link through to South America, China doesn't have Facebook, so its dark, and most of Africa is unfortunately dark, except the big population centers.
Understanding the social graph and then learning how to use it is one of digital's biggest challenges.