Back in 2009, a group of University of Vermont researchers published asurprising paper in the Journal of Happiness Studies. In it, they outlined the process of determining the saddest day in recent memory, the day Michael Jackson died using data culled from blogs. The happiest, they found, was November 4, 2008--the day Obama was elected.
The paper’s underlying concept dates back to 1881, when an Irish scientist conceived of an instrument called a “hedonometer” that could measure the happiness of a population. The 2009 study does something similar, using millions of words scraped from the blogs and ranked according to happiness levels. In 2011, they refined the methodology further and applied it to Twitter alone, analyzing 46 million words.