Africa
Indeed, mobile telephony has huge market penetration in Africa. In fact, it has single-handedly moved the continent forward sixty years (it'd been stuck in the 50's until those mobile antennas started popping up).
In much of sub-Saharan Africa, the most popular payment system is phone-based. In some places it is the only reliable payment system.
You cannot have an economy without a working financial services sector, and that is precisely what mobile telephony has provided in that continent. In turn, the reason why mobile telephony took off in the first place is because it requires relatively little infrastructure.
Huge secondary market too. Back in the day, you used to have the bloke by the side of the road selling his one-litre plastic bottle half-filled with fuel. Nowadays he's using that fuel to run the mini-generator that charges your phone for a small fee.
Biting the hand that feeds IT
