Fox is partially attributing the success to the "twitter effect". So much positive feedback rapidly fed through cyberspace has greatly contributed to people seeing the film multiple times. Many forums have been created already to also contribute to the buzz and runaway success.
With all the talk of the "Twitter effect" and social media making or breaking Hollywood releases, Fox took a decidedly big-picture approach to go to market with the most expensive film ever made.
"Avatar" was a costly gamble for Fox -- its production budget was once confirmed by the studio to be $237 million but believed to have climbed as high as $300 million with an additional estimated $150 million global marketing outlay (a global figure on par with Warner Bros.' "The Dark Knight," the second-highest grossing film of all time). So the studio had to manage its own expectations along with that of moviegoers.