The app is simple to play - decide which of two mutual friends would come out of a fight victorious. Once the decision is made, both fighters receive a notification so spreading the application virally. As the decider you can publish the fight story on your wall and if you don`t like the current fight you always can skip the match.

Once you've played the game a few times, an interstitial appears to introduce prizes only available to fans. This drives new fans.

The application runs a high score table among friends. Alternatively users can check high scores for all of facebook or just those in the UK. The game is easier to win the more friends you have playing, adding a natural network effect

This is a great example of Nudge's social remixing technique - where brand assets, messages and values are mixed with social data (your friends, your photos and stream content) - to create a new fun branded experience on a social network.