Over time, users of Twitter have become less happy and more sad in their communicae, according to a study by University of Vermont researchers, who got published in science journal PLoS.

Data was collected via tracking a vast amount of keywords with differing types of sentiment (some happy, some neutral, others not so happy).   These words ranged from your everyday sentence connectives to more emotive cases like "pancakes" or "suicide."  With this, researchers could calculate the gross domestic happiness amongst Twitter users.