Early rumors had said it was going to be very critical of Facebook founder Mark Zuckerberg. I think he came off as brilliant but socially inept most of the time - although a couple of incidents are hinted at that might make him sinister.
The person who comes off the worst is Napster founder Shawn Fanning who got involved just as Facebook was starting to get big. He's the big bad guy.
A word of caution here. The movie was released by Sony and Columbia - both of whom own record companies and have lots of reasons to hate the first big file sharing website's founder.
Overall, I liked it - and the rest of the audience seemed to as well. If you're a Facebook user (and with 500 million users its a safe bet that you are), you might like to know more about the site that everyone loves to hate - at least a little bit. Go see it!.
BTW, thanks to Andrew at Underdog Studios for the tickets.

If you're investing in internet marketing, Rule #1 is: Keep Your Website On.