This study might help. The Wall Street Journal reports:
“Arthur O’Connor, a doctoral student at Pace University in New York, is testing whether social-media popularity—as measured by Facebook ‘likes,’ Twitter followers and YouTube views—is correlated with stock prices.
“In a pilot study, O’Connor found a ‘statistically significant’ correlation, although he tested only three brands—Starbucks, Nike, and Coca-Cola—over a 10-month period. The more social-media fans a brand had, the better its stock was likely to do, even accounting for general market conditions.”