Gamification, according to Wikipedia, is:
[T]he use of game play mechanics for non-game applications… particularly consumer-oriented web and mobile sites, in order to encourage people to adopt the applications. It also strives to encourage users to engage in desired behaviors in connection with the applications. Gamification works by making technology more engaging, and by encouraging desired behaviors, taking advantage of humans' psychological predisposition to engage in gaming.
Via Stephen Segrave