There is a 9.7 percent increase in happiness on Fridays compared with the worst day of the week, Monday. That is among the discoveries made by Facebook researchers with access to two years of anonymous “status updates” from 100 million users in the United States.
Another conclusion: holidays like the Fourth of July, Thanksgiving and Halloween make Americans happy, while days when celebrities like Michael Jackson or Heath Ledger die make Americans sad. Such insights — obvious though some may be — leap out from the new Gross National Happiness Index, unveiled by Facebook.
http://www.nytimes.com/2009/10/12/te...et/12link.html