The Social Network feels like a strange and satisfying blend of two worlds. On one hand, it’s a classic Hollywood screwball comedy where brainy dialogue ping-pongs with dizzying speed between über-brainy Facebook creator Mark Zuckerberg (Jesse Eisenberg) and his equally tongue-lashing prone peer group. “Dating you is like dating a Stairmaster,” quips his exasperated Boston University girlfriend Erica Albright (Rooney Mara).

But The Social Network also feels, as it should, like a David Fincher (Fight Club, Zodiac) production, steeped in almost perpetual murky darkness as if some Harry Potter overlord had poxed the Harvard campus with an evil spell. The opening scene unfolds in what looks like the light-deprived basement of some serial killer’s lair. In fact, it is the Thirsty Scholar, a Cambridge pub where Zuckerberg experiences a seminal breakup with Erica that haunts him, as writer Aaron Sorkin (working from Ben Mezrich’s book) tells it, through the course of his Facebook career. Zuckerberg may have gone on to create the $25 billion Facebook, but there’s very little evidence in The Social Network that it ever made him happy. It certainly didn’t win him the girl.

This film is about how Zuckerberg — with a little help from his friends, including business major Eduardo Saverin (Andrew Garfield) — came up with the hugely profitable social network as an undergrad at Harvard. The only thing more thrilling than a get-rich story is a get-rich story that imagines (á la Citizen Kane) what hidden trauma drives our genius. For Zuckerberg, it’s two things: Erica and the idea of creating his own exclusive club, a thumbed-nose at the clannish Harvard culture that pushed his nerdy (and Jewish) self to the margins. In this less-than-flattering portrait of a difficult mogul, the computer is where Zuckerberg exercises control and dominance, even though it may be a virtual supremacy. The point is made by an intoxicated and vengeful Zuckerberg, who has just broken up with Erica, creating a malicious program to aesthetically rank girls from the Harvard student body. While he labors over the site in his room, one of Harvard’s upper-echelon clubs busses in pretty girls for a drunken bacchanal. Both events are obnoxious, but only one group ends up with the real girls in the end.

As played by Eisenberg, Zuckerberg is a watchful, smug, suspicious, and distinctly class-conscious sort gazing out from beneath furrowed brows, always ready to lash out at the world before it lashes out at him. When the absurdly WASPish brothers Cameron and Tyler Winklevoss (both played by Armie Hammer) try to interest the programmer nerd in launching a Harvard social network, Zuckerberg at first looks flattered. But then you sense that suspicion returning. Better still, he should just stick it to the WASPs and do it himself. A good chunk of The Social Network takes place in law office conference rooms where the Winklevoss brothers and Saverin accuse Zuckerberg of, variously, stealing their ideas and bilking them out of their rightful share.

Like much in this infectiously fast-paced, whip-smart film (that can at times sink into a too breezy frat-boy tone), the Winklevoss brothers are good fun as self-aware, borderline campy images of blond perfection like something out of Brideshead Revisited. When they come to Harvard’s notorious President Larry Summers (a delightfully droll Douglas Urbanski) for advice about how to contend with Zuckerberg’s thievery, the scene plays out like a vintage Preston Sturges or Howard Hawks film. Summers quips upon first glimpse of the groomed-to-perfection pair, “From the looks of it, they want to sell me a Brooks Brothers franchise.”

The Social Network unfolds with the wildfire energy of any good idea that grows into a great one. As Facebook gains followers, the human architecture of Zuckerberg’s life shifts. Saverin is pushed out by hard-partying Napster co-founder Sean Parker (Justin Timberlake), who talks a mean game but has a weasely way of burrowing into Zuckerberg’s circle of trust.

A ribald geek superhero yarn with a deeply conflicted antihero at its center, the film taps into a key narrative of the Internet age: the online world as a forum for our anger and unmet desires. Without giving away the film’s best joke, even Zuckerberg isn’t immune from the time-suck of Facebook.