In the scene where Sidney first meets Sophie Maes, the man standing directly next to her on the right side of the screen is Brian Austin Green, who was at the time of filming, Megan Fox's fiancé.
The book Alison Olsen is reading in the break room when Sidney sits down with her is "Relative Stranger: Piecing Together a Life Plagued by Madness" by Mary Loudon.
During a scene in which Sidney and Alison are walking along a street in New York together, in one of the shots a shadow of the camera equipment and operator is clearly visible.
When the group is leaving the first party, Eleanor Johnson talks to Sophie Maes before getting into the car. The shot then turns back to Sophie with her saying "Yea" when clearly her lips were not even moving.
Sidney Young: When I was a kid, I used to think there was a special place where all the movie stars lived. A kind of "Shangri La". And if you could just get inside there, you'd be happy. Forever.
About half-way through the credits, the mock-trailer to Sophia's "Theresa" film plays in it's entirety. We find out it's rated NC-17.
Q
How much sex, violence, and profanity are in this movie?
A
For detailed information about the amounts and types of (a) sex and nudity, (b) violence and gore, (c) profanity, (d) alcohol, drugs, and smoking, and (e) frightening and intense scenes in this movie, consult the IMDb Parents Guide for this movie. The Parents Guide for How to Lose Friends & Alienate People can be found here.
Q
Is "How to Lose Friends & Alienate People" based on a book?
A
Yes. How to Lose Friends and Alienate People is a 2001 memoir by British journalist Toby Young.