From “What Facebook Knows,” Tom Simonite’s interesting MIT Technology Review article about the myriad of unexpected ways that the voluminous data Zuckerberg and friends have collected allows the social network to do social science:

“One of [Cameron] Marlow’s researchers has developed a way to calculate a country’s ‘gross national happiness’ from its Facebook activity by logging the occurrence of words and phrases that signal positive or negative emotion. Gross national happiness fluctuates in a way that suggests the measure is accurate: it jumps during holidays and dips when popular public figures die. After a major earthquake in Chile in February 2010, the country’s score plummeted and took many months to return to normal. That event seemed to make the country as a whole more sympathetic when Japan suffered its own big earthquake and subsequent tsunami in March 2011; while Chile’s gross national happiness dipped, the figure didn’t waver in any other countries tracked (Japan wasn’t among them). Adam Kramer, who created the index, says he intended it to show that Facebook’s data could provide cheap and accurate ways to track social trends—methods that could be useful to economists and other researchers.”