Each "node" represents a country - the blue ellipse being relative to the number of the country's population with net access, the white relative to the number that use facebook. Rolling over a node with the mouse brings up the statistics for that country, and you can quickly find a country with the menu on the right. Pressing 'c' displays all the country titles over their respective nodes, and 'r' generates a new configuration [ pointless but fun :) ].