It seems like common sense that an increase in tweets can drive an increase in live TV viewership, but until now there's been scant proof of such correlation. A study released by Nielsen has found just such a relationship. In fact, Nielsen went so far as to use the other c-word: causation.Relying on live TV ratings and tweets for 221 primetime broadcast episodes that were studied using SocialGuide -- a venture between Nielsen and McKinsey & Co. that captures Twitter activity for all U.S. TV programming -- the study found correlations between tweet and tune-in surges. Continue reading at Ad...