Notice how current Facebook user density has followed population density, especially in the USA, Southern Ontario here in Canada, the east coast of Australia, and the west side of India. They also have little to no visitor density in a lot of developing nations and Russia and China, while it is a foregone conclusion this is what it would look like in places like the Amazon jungle, northern Alaska and Russia, the Australian outback, and the African deserts of the north.
Incredibly, FB has 900+ users per 10 sq Miles around Toronto, the Boston-New York-Washington line, London in the UK and the Benelux nations, as well as...northern Turkey?