Mobile carriers are no longer the only game in town for buying content for handsets.

For years, adding games and other content to phones has meant going through carriers' "decks," which are the menus used to buy carrier-approved applications.

Now, US mobile games sold through carrier decks are predicted to generate 72% of revenue in 2012, down from 90% last year, according to Parks Associates' "The New Frontier: Portable and Mobile Gaming" report.

“Off-deck marketing and distribution, combined with new business models such as mobile game advertising, episodic content delivery, and micro-payments, will rekindle industry growth," said Yuanzhe (Michael) Cai, director of broadband and gaming at Parks Associates.

Parks Associates attributed the shift to market forces such as the growing influence of established media companies and experiments with alternative distribution channels and advertising models.

The latter is especially relevant for advertisers and marketers. Mobile users have expressed a repeated preference for ad-supported over fee-based content. As a result, marketers have an opportunity to promote their brands through mobile game giveaways and discounts. Some marketers will also want to associate their brands with specific game licenses (think movie-based games).

Revenue from ads in mobile games are projected to increase more than tenfold by 2012 from 2007 levels, according to Juniper Research's "Mobile Games: Subscription and Download 2007-2012" report.

North American mobile game revenue is predicted to more than double by 2012 from a total of $717 million in 2007, according to Gartner's "More Growth Ahead for Mobile Gaming" report.

Off-deck sales (or marketer-supported giveaways) could help the mobile gaming market grow in a few ways.

Independent developers and publishers who don't have to have their games approved by carriers can potentially offer a wider range of game types, bringing in more gamers.

Off-deck transactions could also mean more money to game publishers by reducing the carriers' cut, incenting additional development. Similarly, such transactions could lower prices for consumers, prompting more sales.

The eMarketer Video Games as a Marketing Channel report will be published in February 2008. Click here to be notified when it is released.