I don't think it defines this generation, so much as lives in it more authentically than any other film. Here's a quote from a review on the DVD cover that calls it emblematic of its time and place, and that I agree with.
Yep, Social Network feels pretty authentic, which is one of its major selling points. Of course, the film is shot in the context of the most distinctly upper class schools in the country, so it's hard for me to consider that an accurate depiction of the college experience, but it ticks a lot of the 21st century boxes in the meantime.
I will say that there are many elements of the film that I passively dislike, although the story is functional and the acting doesn't take me out of the film. It holds up, but I can't help but disagree with any assertion of creativity or ingenuity in the film's storytelling. It follows the exact same pattern of power n' corruption that cinema has run into the ground since Citizen Kane, only this time the protagonist is almost entirely unlikable. Mini House needed a punch in his midget face from frame 1.
What I did love was the ending. Whether Zuckerberg wants to admit it or not, the concept of him starting a social networking site in order to ultimately burn someone and/or gain approval is powerful when placed in the light of that final scene, with him repeatedly hitting refresh, no one left in the large, empty building to comfort him. As Fincher said, the concept of social networking destroying a friendship is incredibly interesting, but the decadence in the interim isn't taken far enough (I mean, come on, Zuckerberg was an asshole from day 1, what's a few months of further assholery supposed to show?), and the inevitable disintegration feels like something to be checked off, rather than a fulfilling culmination of a great story, which I felt it generally was.
It's decent. Fincher has been more ambitious in the past and proved himself more than capable of dreaming big. This film tells a great story in a rather perfunctory manner, but that's not so much my issue (although I do have issues with critics placing a film following an obvious template on a high pedestal); I simply didn't like the characters, and I felt the ones that attempted to deviate from the "everyday 21st century college kid" thing were forced in there for unnecessary comic relief. Well, OK, Timberlake amused me greatly.