Continuity mistake: As Caitlyn types an instant message to let someone know Stephan has been suspended, she makes a :( emoticon. We switch shots to her and then back to the computer and the :( disappears. There is no sound of her hitting the backspace key to erase it, nor does she move the mouse in any way to remove it.
Continuity mistake: When Stephen (Hayden Christensen) and Caitlin (Chloe Sevigny) are talking at the party about Stephen going to law school, you can see her hair is in front of her right ear. In the next shot it's behind the ear and the following shot it's back in front of the ear.
Factual error: The movie uses a "website" of http://members.aol.juktm.html. This wasn't the correct address in 1998 (it would have had a .com in it). The "website" shown was probably a local file on the computer shown in the movie and the producers didn't want to invest the extra time to make a phony address bar.