I like this map. The Facebook Engineering team have created a map with the visualisation of the Facebook friendship links based on your location. The initial sample was from about 10 million pairs of friends and their current city, merged them with lat and longitude functions to get a physical map of connections. As Paul says:
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.
This shows how much Facebook transcends boundaries and helps people keep in touch with their weak and loose ties.