For some reason, we weren't surprised when Derwent Capital Markets announced plans to launch a hedge fund in February that will trade based on something called "Twitter sentiment," among other things. The science behind it comes from researchers at the University of Manchester and Indiana University, which maintains that there is a correlation between public mood and the Dow Jones industrial average. Apparently, a calm public seems to indicate that the Dow will go up, while an anxious public indicates that the Dow will go down. And according to Johan Bollen, an associate professor of informatics and computing at IU, Twitter posts can be analyzed and u