In a Google Tech Talk, Sebastian Deterding talks about how we can apply the concept of Gamification to everyday services and sites. They define gamification as, "integrating game dynamics into your site, service, community, content or campaign, in order to drive participation". They give a few examples such as Nike Plus which tracks exercise, Mint which offers a service to set financial goals and finally in sustainability to create a game out of driving efficiently.
They also discuss a variety of interesting services that offer game design elements anyone can add to their website. They give a few examples such as: GetGlue, CubePoints, BadgeVille and Nitro. After looking at these sites it looks like they offer a variety of services to help retain users, increase loyalty and provide more engagement. A look at BadgeVille's they state that:
Badgeville is a white label Social Rewards & Analytics Platform. We make it easy to increase the loyalty and engagement of your web audience.