Facebook is filled with nothing but farmers and mobsters. While games like Mafia Wars and Farmville are insanely popular on the social networking site, Gareth Davis, platform manager for Facebook, expects a killer app to arrive for the social gaming space soon.

Offering a brief glimpse of his GDS 2010 keynote apeech, Davis told Forbes “What we're about to see is the next level of social game play. The language of social gaming is being invented and we have a few of the building blocks, but many more are about to be discovered.

“There will be a killer app for social games in the same way that Mario was for Nintendo, Sonic was for Sega and Halo was for Xbox. We're going to have our Halo, our Mario, soon.”

Don’t expect this “Halo” will come in the form of Farmville 2, however, as Davis is certain that the future game will be different.

“I think FarmVille is a great game, but it is a light simulation that has mass appeal. I think that we will see a new kind of game that people have not really seen before. It may have a traditional IP on it, it doesn't have to be completely out of left field, but we're expecting those great experiences to show up.”

 Davis points out that Facebook has acquired 400 million monthly users, 100 million of which play games on a monthly basis. Is it possible that these millions of gamers could soon be playing games from big-name publishers? With Madden and Civilization already heading to Facebook, Davis also reminds that more is coming.

“This year you'll be seeing some more major Triple-A brands - console and PC brands - come to Facebook.com,” Davis concluded.

Do you think Facebook could feasibly become a contender in the hardcore gaming market? Or are its users forever destined to harvest crops and gift fedoras?