"America, are you happy ? The emotional words contained in hundreds of millions of messages posted to the Twitter website may hold the answer.
Computer scientist Alan Mislove at Northeastern University in Boston and colleagues have found that these "tweets" suggest that the west coast is happier than the east coast, and across the country happiness peaks each Sunday morning, with a trough on Thursday evenings. The team calls their work the "pulse of the nation".[...]" Excerpted from "Twitter mood maps reveal emotional states of America" :
by Celeste Biever, in 'The New Scientist' (July 21, 2010)
US mood throughout the day inferred from Twitter
green = happiness | red = unhappiness