http://www.slate.com/id/2269250/
It seems that most of the specific evidence Sorkin cites is fictional. If Slate is correct, the site was egalitarian. If the transcripts of Zuckerberg's blog are believable (Google them if you want; they're not hard to find), then Sorkin wrote most of the inflammatory material.
It is interesting that people who don't know the story very well still zero in on the fictional details Sorking added as the most upsetting. In a way, it must vindicate Zuckerberg. Unfortunate that those readily-identifiable details are so memorable.