[Facebook] was zero-rated in 2010—that is, made almost free of data charges in several African markets (the bill is footed by Facebook, the network operators and the phone manufacturers)…. So while text messages are cheap, sitting on Facebook is even cheaper. Facebook’s own numbers show growth coming fastest in Egypt, Morocco, Nigeria, Kenya and South Africa.
There were about 17m Facebook users in Africa at the start of this year, and there are expected to be 28m by the end of it. … The number of Facebook users in Tanzania quadrupled in 2010, to 200,000. It is expected to quadruple again this year, giving Tanzania more Facebook users than graduates…. About 140,000 Tunisians joined Facebook every month last year.