Twitter's Presidential Index (Twindex)

Polls have traditionally been used to measure political candidates, but with the advent of the cell phone they have certainly had to overcome recent hurdles.  Twitter now has come up with a new formula which weighs support vs. negative feelings for a presidential candidate.  Their site and this NYTimes article does not explain what exactly the numbers are, but it is obvious they are correlated to the Gallop poll numbers (which you can see in the article).  The site will be updated each evening.