Over the weekend, the biggest mystery among fans of Stieg Larsson's Girl with the Dragon Tattoo series was a 90-second red band trailer (that is one that the ratings board at the Motion Picture Association of America has deemed appropriate for all audiences) which mysteriously showed up on YouTube on Saturday. The first look at David Fincher's English-language adaptation of Larsson's novels, the trailer features rapid-fire shots of stars Daniel Craig and Rooney Mara, while a cover of Led Zeppelin's "Immigrant Song" by Trent Reznor (who wasd also Fincher's musical collaborator on The Social Network) and the Yeah Yeah Yeahs Karen O blasts on the soundtrack.

All in all, it's a great trailer, but nobody's taking responsibility for it. Sony, which is releasing the film on December 21, isn't linking to the footage, nor have they demanded that YouTube user dobvlvstiuwir take down the footage, which is clearly real, and has already been viewed more than 1.4 million times. Officially, Sony is saying the trailer was illegally recorded before a screening of The Hangover II this past weekend.

Fine, but then why not just link to an official version? And isn't a bit curious that dobvlvstiuwir only joined Youtube the day the video was uploaded? That, and the exceedingly high quality of the footage prompted the Hollywood Reporter's Gregg Kilday to lay out the case for the teaser as a stealth-marketing ploy for the film. Practically, it makes sense, notes Kilday, since "leaking it via YouTube means the studio doesn’t have to go through the exercise of making the video an 'age-restricted' posting on its official site" and the buzz can only help build anticipation for the film. (Kilday also shoots down the suggestion that the footage came from a European theater: "[T]he trailer is preceded by an MPAA red-band, advising that the preview has been approved by the MPAA for mature audiences...why would theaters in Europe be showing an MPAA advisory which is aimed at U.S. moviegoers.")

Our take: it's a buzz-building effort by the studio, yes, but also an ingenious way of getting around Led Zeppelin's pricey licensing fees.