A map of connectedness:
William Easterly picks up on a couple dark spots:
One interesting pattern is a kind of Facebook Curtain somewhat related to the old Iron Curtain. The whole area including the former Soviet Union and China, along with other adjacent autocracies like Burma and North Korea, is pretty much a Facebook void … This reflects some combination of language barriers, preference for other social networks in Russia and China, and some (rather unclear) role for Internet censorship by the authorities, which either prevents or lowers the payoff to participating in Facebook.
Thorsten Gaetz remixes the map to highlight these non-Facebook regions.