That is a playlist of the songs that Stephenie listened to when writing the book. The film prodoucers, director, and music editors look to her list just like they did with Twilight and try to incorprate some of the music she has on her list into the film. So far I know Muse, The All-American Rejects, and possibly Blue October, will be on the soundtrack. I also know that Band of Skulls, The Used, Milow, and Radiohead's Thom Yorke and Bon Iver were also being looked at to join the soundtrack.
So the list Stephenie has up on her page was some of the music she listen to when writing the book and the B,J and E were from who's point of view the song was coming from.