In a first attempt at establishing a causal relationship between Twitter activity and TV ratings, Nielsen on Tuesday released a study that suggests that the social media platform can in fact have a meaningful impact on GRPs. According to Nielsen’s “Twitter Causation Study,” the volume of tweets related to a particular broadcast “caused significant changes in live TV ratings” 29 percent of the time. While Nielsen did not further quantify the impact of increased tweet volume on a given show’s ratings—as was born out with Syfy’s much-ballyhooed...