Why does Kenya lead the world in mobile money?

PAYING for a taxi ride using your mobile phone is easier in Nairobi than it is in New York, thanks to Kenya's world-leading mobile-money system, M-PESA. Launched in 2007 by Safaricom, the country's largest mobile-network operator, it is now used by over 17m Kenyans, equivalent to more than two-thirds of the adult population; around 25% of the country's gross national product flows through it

http://www.economist.com/blogs/economist-explains/2013/05/economist-explains-18