You can do interesting things with data, in this case a Facebook engineer has taken all the Facebook friend relationships and mapped them out producing the following image.
Click here to view a high rest image of this
Every relationship was rendered as a line between the 2 points that those users were registered as being located at. The above image is only this data but you can quite clearly see an outline of the world.
To find about the process used to create this graph, http://www.facebook.com/notes/facebook-engineering/visualizing-friendships/469716398919