Christopher Mims analyzes Zuckerberg's strategy in the developing world. His company has hugely grown its user base by making Facebook freely or cheaply available on unsophisticated cell phones, which is the only way millions are able to access the web:

For the same reason that companies like Unilever are so keen to guarantee that the first shampoo a newly minted member of the global middle class ever tries is a brand they make, Facebook wants to completely own its users’ first contact with the web. The lifetime value of these users could, in the long run, be the main way for Facebook to justify its share price. And it gives Facebook, in a way that not even Google has accomplished, the chance to become the world’s homepage.