Since the inception of social media, a prodigious amount of status updates, tweets, and comments have been posted online. The language people use to express themselves can provide clues about the kind of people they are, online and off. Current efforts to understand personality from writing samples rely on theories and survey data from the 1980s. New research from the New England Complex Systems Institute (NECSI) uses social media data to successfully identify differences and similarities between users without prior assumptions. This is a step toward building a better understanding of the psychology of human personality.