I think the story is quite familiar. Zuckerberg is being sued twice, first by the people that claim Zuckerberg stole the idea from and the second lawsuit from his (former?) friend and business associate. The movie is set in those two different lawsuits and the story is mainly told through flashbacks, sounds boring? Not with David Fincher and scenario writer Aaron Sorkin as they succeeded in keeping this movie interesting through amazing dialogues.
I also was a bit worried by the length of the Social Network but the two hours were done before i realized.
One of the other strongpoints of this movie is the great soundtrack by Trent Reznor and Atticus Ross. And (i’m going to put this in a spoiler, select the text to read) the fact that the Winkelvoss brothers are played by one actor is simply stunning, i didn’t find out until after the movie. Something else that struck me was the role Justin Timberlake played, which was actually pretty good. Something i didn’t expect either from a ‘singer gone actor’. Pretty highly recommended, even if you dislike social networks.