So some physicists decided to try and predict the stock market movements and they found that they could predict with 80% confidence the movement of the Dow with...
Apparently the "calmness" of Twitter had the highest correlation. However, they had no explanation, just a correlation, so I'm not ready to start investing based on Twitter. But, this could be a new way to look at investor sentiment.
If you want to read a more thorough analysis of the paper, check out http://www.technologyreview.com/blog/arxiv/25900/?ref=rss