FORTUNE — When Disney released its new Muppets movie, the studio made use of a different kind of focus group to predict box office sales: the Twittersphere. Big movie studios are increasingly tapping into hundreds of thousands of tweets to plot their marketing strategies, deciding which trailers and ad campaigns work, and even whom they should cast in their next films. Disney (DIS) gets its social media data from a startup called Fizziology, which analyzes the online reactions by fans for every major movie released. Fortunately, no one in the Twittersphere wants to replace Miss Piggy. —Jennifer Alsever

This article is from the February 27, 2012 issue of Fortune.