Researchers have built what Chris Danforth calls “the Dow Jones index of happiness,” using the frequency of key words culled from Twitter. Danforth and other researchers look at about 50 million tweets a day (about 10 percent of each day’s total) and have done so since 2008. They (or rather their super-techy Twitter measuring device) scan the tweets for key words such as happy, sad, love, tragedy or many others to gauge how folks are thinking about a given day. “You can think of this instrument as operating in the manner of a thermometer,” Danforth says. “Each molecule represents one tweet, and in aggregating hundreds of millions of words we get a sense for the emotional temperature of large populations.” Perhaps it’s no surprise that Christmas and Christmas Eve are typically incredibly happy and merry days, according to the research. Other holidays such as Valentine’s Day, Easter and Mother’s Day see an uptick of Twitter-registered joy. Days in which tragedies occur—the Japanese tsunami of 2011, the Newtown shootings in 2012, etc.—are among the saddest days on record. Also worth noting: Twitter users may be growing sadder—though Danforth notes that trends of this nature are harder to parse. “The demographics certainly have changed during this time period, so some of the decline (seen on graphs) is a result of the shift in population. We see simple negative words (no, never, won’t) being used more frequently now than a few years ago.” (ABC News)

Paul Asay has covered religion for The Washington Post, Christianity Today, Beliefnet.com and The (Colorado Springs) Gazette. He writes about culture for Plugged In and wrote the Batman book God on the Streets of Gotham (Tyndale). He lives in Colorado Springs with wife, Wendy, and two children. Follow him on Twitter.