Game mechanics are not games. They are the rules and principles that guide a person through a series of activities while providing feedback as to progress and performance and delivering rewards for accomplishments.
Game mechanics are deeper than pins, badges or levels, they are mechanisms that harness the power of fundamental human needs.
If you understand fundamental human needs and how they apply to game mechanics you will be able to design software interactions that are compelling and engaging for the people who us the software. This presentation discusses the psychology of motivation and the basics of game mechanics.