The hundreds of billions of dollars made when mobile phone networks started operating across most of Africa could be repeated with internet services.

However, it is my understanding that internet at the moment across most of Africa is trending towards UMTS and another wireless technologies that leverage the existing towers built for mobile access.

A single such tower covers a far wider area and is much cheaper to install and maintain than broadband cables. Also, factoring in that Africa is not very densely populated, I would think that wireless makes sense over wired.