"With seven million or more messages being tweeted each day, this data stream potentially allows us to take the temperature of the population very quickly," Smith said. "The results are noisy, as are the results of polls. Opinion pollsters have learned to compensate for these distortions, while we're still trying to identify and understand the noise in our data. Given that, I'm excited that we get any signal at all from social media that correlates with the polls.
via sciencedaily.com