The average number of followers boasted by Twitter users that mention top brands grew sharply in the first half (H1) of 2012, according to the Bazaarvoice Conversation Index Vol. 5, released October 2012. The average number of followers jumped from 1183 in January to 1566 in June among users that mentioned 1 or more of 13 major brands examined. This heightens the opportunities and risks for these brands. On the one hand, increased amplification of positive mentions could prove a boon. On the other hand, negative mentions could escalate PR crises in a hurry. Read the rest at MarketingCharts.