BUYING a mobile phone was the wisest $20 Ranvir Singh ever
spent. Mr Singh, a farmer in the north Indian state of Uttar
Pradesh, used to make appointments in person, in advance, to
deliver fresh buffalo milk to his 40-odd neighbours. Now his
customers just call when they want some. Mr Singh's income has
risen by 25%, to 7,000 rupees ($149) a month. And he hears
rumours of an even more bountiful technology. He has heard that
“something on mobile phones” can tell him the current market
price of his wheat. Mr Singh does not know that that “something”
is the internet, because, like most Indians, he has never seen
or used it. But the phone in his calloused hand hints at how
hundreds of millions of people in emerging markets—perhaps even
billions—will one day log on.  Only 81m Indians (7% of the
population) regularly use the internet. But brutal price wars
mean that 507m own mobile phones. Calls cost as little as $0.006
per minute. Indian operators such as Bharti Airtel and Reliance
Communications sign up 20m new s