By Will Oremus
Facebook just made its boldest business move ever, buying the mobile-messaging service WhatsApp in a deal worth some $19 billion in cash and stock. That’s six times what Google paid for Nest in January, and 19 times what Facebook paid for Instagram two years ago. It’s so much money that people found themselves reaching beyond the business realm for context. Development expert Charles Kenny compared the purchase price to the total annual lending of the World Bank.