The World Well-Being Project
http://www.wwbp.org/

The World Well-Being Project (WWBP) is a group of computer scientists, psychologists, and statisticians collaborating to develop new techniques for measuring psychological and medical well-being based on language used in social media.

In a study published in the journal PLOS ONE, the researchers used data from 75,000 people to generate computer models that were able to predict the individuals' age, gender and their responses on the personality questionnaires they completed. The researchers were 92% correct in predicting users' gender based only on the language of their status updates.