How does Twitter describe our moods?

As of February 2010, Twitter was getting about 50 million tweets per day. That much data allows social scientists to study human behavior in new ways. Sociologists at Cornell studied a smaller set of tweets looking for indications about how these messages describe our moods. Apparently, moods are similar across cultures. We all seem to dislike Monday mornings, and get cheerier as we move towards the weekend. It may be that Twitter behavior doesn't generalize to all people, but it will be interesting to see over time what other conclusions can be drawn from these short messages.