I liked it, and I think I'll like it even more with repeated viewings. David Fincher has a track record of directing movies that I really enjoy (cf. Fight Club, Se7en, Zodiac; I even thought Panic Room was pretty okay), so I wasn't surprised that he managed to take a subject as potentially dull as the founding of a glorified, cooler-looking, less-spam-bot-infested MySpace and turn it into something pretty slick.
That said, there's some interesting conversations going on about what many perceive to be the movie's less-than-flattering portrayal of Facebook founder extraordinaire Mark Zuckerberg. And I won't deny that there are moments within the film that make Zuckerberg come off as kind of an unlikeable asshole (or as a guy trying really hard to be one). But ultimately, I think he's portrayed as what he really is--a guy with a Pretty Cool Idea who wasn't afraid to run with it and who stuck to his guns when people came after him. You could argue that such qualities constitute being an asshole, but I have to admire Zuckerberg nonetheless, in the same sort of way I admire Harlan Ellison or Chuck Yeager--not the nicest guys in the world, but so damn smart/ballsy/determined that ultimately "nice" or "friendly" or "playing well with others" has little to do with it. "Nice" is not necessarily a quality of greatness, after all.
"But Alex!" you shout in perturbation. "There are also reports that the movie takes liberties with the facts! Maybe that's not who Zuckerberg really is!" Well, yes, I don't doubt it, especially given that the movie's based on a book which the most helpful Amazon review describes as "Tabloid Quality Dramatic Narrative" and which reportedly received most of its info from Eduardo Saverin, whom I doubt is chumming it up with Zuckerberg at the moment. (Zuckerberg himself has called the movie "fiction.") I doubt that the real Mark Zuckerberg is as socially inept and self-absorbed as the movie would have you believe; it's entirely possible he's really just some okay dude who's being smear-campaigned with Winklevoss-endorsed libelous truthiness.
But ultimately, so what? Even though I don't necessarily think the movie's portrait is that negative in the first place, I suspect Sorkin and Fincher could have made Zuckerberg out to be a maniacal homophobe who bathes in infant's blood and is currently turning FarmVille property into virtual kolkhozy and sokhozy to set up his own internet dictatorship, and he'd still be the youngest billionaire in the world. Why? Because everyone uses Facebook. Well, almost everyone. I can count on two hands the number of people in my age group who aren't currently on Facebook; I can count on one hand the number of people in my age group who haven't ever been on Facebook. (There are precisely two, and one of them had a MySpace.) Besides, the movie isn't even really about Facebook itself; it's about this guy with an idea and how he made it work, and the stuff that happened to him along the way, and that's what makes it interesting.
Oh, and the soundtrack's pretty nifty too. My previous reactions to Trent Reznor's work has been along the lines of "all right, not too bad, but nothing that gets me super-pumped," but he's (along with HDA bandmate Atticus Ross) done a pretty awesome job with the soundtrack. Check it out for sure.