#1. I read about these "challenges" what are they and how does one go about starting one?

#2. I have noticed that sometimes if I use Expedia or Travelocity, I can find Continental Flights ticketed on Northwest Tickets that are cheaper on the same route as tickets ticketed on Continental. However, I am never able to find flights on NWA operated by Continental. Is this an Expeida/Travelocity anomaly or am I doing something wrong?