This is pretty amazing: researchers from Harvard and Northeastern universities took more than 300 million tweets over three years and analyzed them to create a graphic (and video) of America's mood at any given time and in any given place.

Researchers Analyze 300 Million Tweets to Create Mood Ring for America

Above is the graphic that the researchers came up with (click to enlarge it), after an arduous process to determine the "24-hour Twitter mood cycle of the United States."

The group's web site explains the reasons for why—and the methods by which—they conducted the research:

In analogy to individual neurons firing together to add up to the human consciousness, the billions of tweets have meaningful macro-states that contain information about the whole system rather than the individual tweeters. But we need to do a little data mining to extract meaningful information about these states, to expose our collective states of mind.

As a proof-of-concept we've1 been studying the mood of all of the public tweets. While there are many services that will allow you to study the mood of your own tweets (and also an neat little DIY project to show you the global average of twitter), much less effort has gone into studying how the mood breaks down according to geography.

Pretty cool, yes? But we're not done yet! The researchers also created a time-lapse video that allows you to see the cycle in action as our collective moods were tallied over a 24-hour period (below the video, their explanation for how to interpret it):

Here are the notes the researches had with regard to the video:

In the video, green corresponds to a happy mood and red corresponds to a grumpier state of mind. The area of each state is scaled according to the number of tweets originating in that state. Note how the East Coast is consistently 3 hours ahead of the West Coast, so when we're sleeping in Boston, the Californians are tweeting away. It's also interesting that better weather seems to make you happier (or rather, that better weather is correlated with happier tweets): Florida and California seems to be consistently in a better mood than the remaining US. Also note how New Mexico and Delaware behave very differently from their neighbors. Full results, individual maps, and a high-res poster can be found on the dedicated Twitter Mood website.

So, what do you think? How about this: consider what time(s) of day you're in your best mood, and what time(s) of day you're in your worst mood, pair it with your location, and see if the data fits your personal experience.

[Harvard's Complexity and Social Networks Blog]