Language in social media reveals a lot about people’s personality and mood as they discuss the activities and relationships that constitute their everyday lives. Although social media are widely studied, researchers in computational linguistics have mostly focused on prediction tasks such as sentiment analysis and authorship attribution. In this paper, we show how social media can also be used to gain psychological insights. We demonstrate an exploration of language use as a function of age, gender, and personality from a dataset of Facebook posts from 75,000 people who have also taken personality tests, and we suggest how more sophisticated tools could be brought to bear on such data.