Social recommendation firm Trusted Opinion is adding a social game platform to get its community of a million restaurant fans to engage in the network and spend more money.

In doing so, the company is taking part in a trend dubbed “gamification,” or the use of game mechanics to enhance the interest in non-game applications. The topic was the subject of a panel last week at the Casual Connect game conference in Seattle.

There are lots of companies gamifying their web sites or talking about doing it, as brands realize that young users are more likely to engage with game-related content. They can turn to books such as Gabe Zichermann’s Game-Based Marketing or to companies such as BunchBall or BigDoor Media.

So far, Trusted Opinion has more than 1.5 million restaurant reviews from its 1 million users in 100 countries. Trusted Opinion believes that its social gaming elements will increase the quantity and quality of user participation in what to date has been a purely informational review site. Now the company hopes to become a social destination where users can come back over and over to interact with friends. The game elements include virtual coins, gifts, badges, and regional leaderboards that get users competing and socializing with each other. Gamers are rewarded for their expertise. Members can buy virtual coins with real money and send virtual gifts to users, awarding them “respect” points for their reviews. Members can become “gurus” of their regions as they collect respect points. The virtual currency is supported by online payment systems such as PayPal.

All sorts of companies are doing the same thing, from NBC Universal to FourSquare.

Palo Alto, Calif.-based Trusted Opinion was founded in 2005 and has raised $4.7 million. The company has 15 employees. It competes with Oype, Yelp, CitySearch, and Urbanspoon. To compete better, Trusted Opinion is trying to personalize recommendations based on a user’s tastes and opinions from friends and experts.