DAVID, a Masai herdsman from Kisumu in Kenya, answers a call on his cellphone. After listening to the message, he repeats a short phrase in his Masai dialect. He then listens to another short message, and repeats the new phrase. After 30 minutes, he ends the call, having earned enough for a week’s worth of personal cellphone airtime.

Cellphones tap wisdom of the crowds – 11 February 2009 – New Scientist