Some random dude named Ruslan Enikeev, took 350,000 websites on the internet, and arranged them in a vast map, organised by visits and location. One websites proximity to another also depends on where people normally go from a site. If more people go to Facebook, than Wikipedia, from Google, than, Facebook will be closer. The exact algorithm used to arrange these sites is not available, but there’s some useful ingo in the about section.
Check out the map of the internet here.