In a continent with limited infrastructure, phones serve as income boosters, a teaching tool and wallets, according to speakers during a session at the Africa 2.0 forum.

The predominance of pre-paid phones in Africa means that "air time is exactly equivalent to cash," said Nathan Eagle, CEO of Txt Eagle, a company he started in 2008 that aims to help mobile-phone users in developing nations earn income with their handsets.

With Africans spending 10 percent of their yearly income on air time, Eagle said the question becomes: "How can we think of the phone as a mechanism to compensate people?"

For Txt Eagle, this means compensating users for providing the company with data. While working on a health-care project that called for nurses in rural Kenyan hospitals to send a text message on blood supply information to a central database, Eagle discovered that paying the nurses for their messages and giving them air time credit directly affected their participation.

Not covering the cost of a text message was "essentially asking them to take a pay cut," he realized when participation plummeted after one month.