Opening paragraphs..............

     If you want to measure the world's emotional state, to find a mood ring large enough to encircle the globe, you could do worse than Twitter,  Nearly one billion human beings have accounts, and they post roughly 6,000 tweets every second.  The sheer volume of these minimessages - what people say and how they say it - has produced an ocean of data that social scientists can swim though to understand human behavior.
     A few years ago, two Cornell University sociologists, Michael Macy and Scott Golder, studied more than 500 million tweets that 2.4 million uses in eighty-four countries posted over a two-year period.  They hoped to use this trove to measure people's emotions - in particular, how "positive affect" (emotions such as enthusiasm, confidence, and alertness) and "negative affect" (emotions such as anger, lethargy, and guilt) varied over time.  The researchers didn't read those half a billion tweets one by one, of course.  Instead, they fed the posts into a powerful and widely used computerized text-analysis program called LIWC (Linguistic Inquiry and Word Count) that evaluated each word for the emotion it conveyed.
     What Macy and Golder found, and published in the eminent journal Science, was a remarkable consistent pattern across people's waking hours. ...

-Daniel H. Pink,  When:  The Scientific Secrets Of Perfect Timing

Ed. Note:  To read the Macy and Golder study, go here