And the ones like me, the mousy nobodies, we don't always turn out to be the heroes of the tale. Sometimes we have our own dark secrets.”
-- Katie (chapter 3)

Importance: The is the first real look at Katie, who is sort of the outcast in the group, and her words hint that there is something sinister in her life. This is one of many red herrings, obviously meant to encourage the reader to consider Katie as a suspect in the murder. Katie is comparing her group to the characters of a romantic comedy, and in that situation the “mousy” girl always becomes the heroine.

When you learn how isolated an environment this really is, you realize that only freaks would choose to live in a place like this. People running from something, or with nothing left to lose. People like me.”
-- Heather (chapter 5)

Importance: Heather is talking about the fact that people like Emma's group sign...