Currently there are around 3 billion mobile phone subscribers. By 2015 this number which is expected to reach 5 billion when, according to Nokia, two out of three people in the world will have a cell phone.
Through a combination of a growing coverage with a cheaper technology, mobile telephony is slowly bypassing many obstacles that poor infrastructure has put in the way of economic development:
To the astonishment of the industry, people living on a few dollars a day have proven avid phone users, and in many parts of the world cellular airtime has become a de facto currency. The reason is simple: a mobile phone can dramatically improve living standards by saving wasted trips, providing information about crop prices, summoning medical help, and even serving as the conduit to banking services.
This trend will continue as cell-phone makers and service providers are one-by-one discovering the top dollar at the bottom of the pyramid. More in the BusinessWeek article.