from FT article.
About 2.5bn people in emerging markets have mobile phones. … Consider what happened two-and-a-half years ago when the Haitian earthquake struck. …researchers at Columbia University and the Karolinska Institute took a different tack: they tracked Sim cards inside Haitians’ mobile phones. That helped them to “analyse the destination of more than 600,000 people who were displaced from Port au Prince”
Twitter and Facebook. These are strikingly popular in emerging markets; Indonesia, for example, has one of the world’s most Twitter-addicted populations. Thus a sudden increase in certain keywords can provide early warning of distress. References to food or ethnic strife may indicate cialis online incipient famine or unrest.