A criticism you hear a lot of Ayn Rand's fiction is that her characters aren't really characters at all but are merely broad, improbable caricatures. I think this is based on mistaking 'romantic' or 'large-than-life' for 'caricature.' Romantic characters are larger-than-life embodiments of ideas, personality traits, psycholical attributes, philosophical positions, etc., carefully designed to help convey the author's theme.
Rand's novels work for me because her characters are spectacularly and romantically grand and, as others have pointed out, Rand -- perhaps uniquely in all of literature -- takes great pains to include the philosophical and biographical background details that illustrate how her archetypal characters came to be who they are.
The Social Network doesn't work for me because it actually does what people acuse Rand of doing. I don't know anything about the real Mark Zuckerberg, other than that he founded and grew Facebook when he was very young. I'm fascinated by people who achieve extraordinary success at a very young age, particularly when that success is the result of both extraordinary ability and extraordinary effort and perseverance. This man is the world's youngest billionaire, for crying out loud! I'd like to know what makes him tick.
Instead, we get an opening scene in which he acts like and asshole towards a sweet-faced girl. She calls him an asshole. He goes home and blogs about her in an assholic fashion. We get it. Mark Zuckerberg is an asshole. We're supposed to accept it at face value. I've met thousands of assholes in my lifetime. None of them created Facebook. There's got to be something more to this guy than that (other than the fact that he wanted to meet girls).
The approach extends through the whole movie in progressively more laughable and cliched scenes. My favorite was the moment in which a character who is being unceremoniously forced out of the company is literally left standing out in the rain. Honorable mention goes to a scene in which an unstable character with excessive appetites is shown with a group of people doing what... that's right: blow off of a co-ed's belly.
I will, however, give the filmmakers a free pass on the fact that two supporting characters (representatives of the monied, establishment Harvard student community) look so much like they just stepped off the pages of the Brooks Brothers catalog that a third character is actually compelled to comment on it because apparently that's exactly what these two douchebags look like. They also row crew. Some things you just can't make up.
And finally, as someone who has written software code, I would like to share the following public service announcement with the filmmaking community: coders very rarely pound on their keyboards with the force of a pneumatic drill. Sometimes if we need to count out a certain number of keystrokes (e.g. I need a string consisting of 37 spaces) we'll sort of bang on that one key a little as we count, but generally we just type like anyone else who is proficient with a keyboard. We're nerds. We know there is no correlation between how emphatic we are about something we're typing and the force with which we strike the keyboard. Only a n00b (or filmmaker) would think otherwise.