I just spent a year in Cape Town, and one thing I found interesting was that due to the utter incompetence of the monopoly telco (Telkom), people tend to get their internets from mobile-based technologies. I've heard that Nairobi (the major non-SA tech hub in Africa) is much the same way.

As smartphones become commoditized, I expect mobile social networking to become dominant quicker there than in the EU/US, or at least to 'skip a technology' and move straight to mobile without an intervening landline-based phase.