"Those data sets contain all sorts of information about the developing world, whether workaday economic statistics - gross domestic product, consumer price inflation, and the like - or arcane information like how many women are breast-feeding their children in rural Peru.
"It is a trove unlike anything else in the world and highly valuable. For whatever its accuracy or biases, this data essentially defines the economic reality of billions of people and is used in making policies and decisions that have an enormous impact on their lives."
Read more in the NYT article.