Extras by Scott Westerfield. Book 4 in Scott's series that included Pretties, Uglies, and Specials.
This book will be published this month. It is the future of Earth where all people are judged by their face rank (kind of a YouTube society). A girl named Aya Fuse will kick up her face rank by exposing whoever is riding the Mag-Lev at night. Things go quickly down hill from there as she discovers aliens who are out to destroy the planet and meets Youngblood whose face rank is #1.
