What do 10 million Facebook friendships look like? It pretty much looks like the world at night from space. Facebook intern Paul Butler made the map and was surprised by how elegantly it lit up the world. Facebook has truly gone global. From his Facebook post about the map:
I was interested in seeing how geography and political borders affected where people lived relative to their friends. I wanted a visualization that would show which cities had a lot of friendships between them.
To make the map Paul looked up 10 million friendship pairs, and listed the friends by current city, then tabulated the number of friendships between cities. He then mapped this connection strength to the latitude and longitude of the city.
The data rendering was a little bit more complicated, as Paul explains in the post:
I defined weights for each pair of cities as a function of the Euclidean distance between them and the number of friends between them. Then I plotted lines between the pairs by weight, so that pairs of cities with the most friendships between them were drawn on top of the others. I used a color ramp from black to blue to white, with each line’s color depending on its weight.
Many of the areas with few connections are regions with small populations (hello, Sahara and Amazon!) or low internet penetration. And the lack of connections to China would be because the government blocks Facebook access, though there is an almost identical site called Ren Ren Wang.
The dark vastness of Russia is explained by the fact that Facebook is only the seventh most popular social networking site in the country, with only two percent of Russia’s online audience using it. But it still beats MySpace, so that’s really all that matters.
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Image: Facebook Engineering Page