The rise and legal fallout surrounding Facebook and its creator Mark Zuckerberg is explored to compelling effect by Fight Club director Fincher and West Wing writer Aaron Sorkin. Jesse Eisenberg plays the Harvard computer whiz who turned a modest online community into a global phenomenon. But how much of it was his idea? Andrew Garfield feels the sting of betrayal as Zuckerberg's ex-best friend and bank-roller Eduardo Saverin while Justin Timberlake sniffs a golden opportunity as Napster founder Sean Archer. The most relevant morality tale of the internet age? Click to confirm.
What's on your mind? Well, if you're a Facebook user - and since there are over 500 million of them, you probably are - you ought to forget about updating your status for a couple of hours to catch one of the juiciest dramas of the year.
Granted, the story of a bunch of nerds (and a couple of jocks) setting up a website and falling out about it doesn't sound like a particularly enticing prospect.
"Based on the same research as" Ben Mezrich's book The Accidental Billionaire, it mixes fact and careful speculation to tell a story of trust, loyalty, friendship, honesty and respect. Or at least the disintegration thereof.
As with so many such tales, it all starts with a girl. Bitter at being dumped, supergeek Zuckerberg (Eisenberg) grabs a beer and rustles up a website allowing fellow students to rate female undergrads on looks.
Unsurprisingly, the stunt gets him in all kinds of trouble. But, after crashing the campus server within hours, its popularity can't be denied.
Liking the geek's style, future Olympic rowing twins Cameron and Tyler Winklevoss (both played by Armie Hammer thanks to neat digital trickery) enlist Zuckerberg to flesh out their own vision for an online Harvard clique.
Zuckerberg takes the idea and - bankrolled by his best pal Saverin (Garfield) - runs with it, using his own code to produce a bigger, better version that spreads through the Ivy League like wildfire.
Understandably, the cheated brothers want blood ("I'm six-five, two-twenty, and there's two of me," snarls one).
But while they opt to take legal rather than physical action, up pops Napster entrepreneur Sean Archer (Timberlake) to bring a little West Coast rock'n'roll to proceedings.
Which is where the fun and serious games really begin.
The drama is presented as a three-way argument between Zuckerberg, Saverin and "the Winklevii". Whose version of the truth you believe - and they're all true in the legally-settled-with-non-disclosure-clauses sense - is down to personal interpretation.
As jealousy, naivity, and even some shameful business with a chicken gradually creep into the mix, Fincher and Sorkin have a fine time toying with everyone's allegiances.
The potent score from Nine Inch Nails' Trent Reznor adds dramatic oomph, while Sorkin's script delivers everything a cast of talented up-and-comers could wish for.
With Garfield, Hammer and Rooney Mara confirming their face-to-watch status, Timberlake builds impressively on the promise of the underseen Alpha Dog, and Eisenberg polishes his nerd-savant act to perfection.
The real Zuckerberg may not become a fan, but irony lovers will lap up this splendidly disconnected portrayal of a man whose business is built on connecting people.
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