10 Lessons from the 2009 Box Office

In the old days — like, until this summer — a movie studio judged the success of its big pictures by how much they grossed on the opening weekend. But in the age of Twitter, electronic word-of-mouth is immediate, as early moviegoers tweet their opinions on a film to followers who retweet them, and so on. Instant-messaging can make or break a film within 24 hours. At any rate, something viral happened to Brüno, Sacha Baron Cohen's followup to Borat. Its opening-day gross was a burly $14.4 million, which that Saturday plunged an abysmal 40%. Somebody got out the word — stinker — and did it quick, possibly in 140 characters. The movie's opening-weekend total was $30 million, and it's taken six weeks to earn its second $30 million. Moral: The fate of a movie that might have been two years in the making can now be determined in a couple of hours on a Friday night. That's comics in the Twitter age.

See 10 ways Twitter will change American business.