The Facebook games that millions love (and hate)

READ on CNN.com: "Early each morning, millions of farmers around the world rise to toil in their fields. By night, gangs of mobsters scheme and legions of poker players shuffle up and deal.

Sure, none of it's real. But the overwhelming popularity of so-called social gaming -- simple games that let people play with their friends on networking sites such as Facebook -- is changing the face of video games, experts say.

And as the maker of popular titles like FarmVille and Mafia Wars, San Francisco, California-based Zynga has ridden the games' skyrocketing popularity to the top of that emerging market.

For Zynga founder Mark Pincus, the formula for gaming success on Facebook, MySpace and other sites was as simple as it might seem counterintuitive: create simple games that people like but can easily set aside.

'We built the games so they could be played in a tab on your browser while you're on a conference call,' said Pincus, a veteran Web entrepreneur who created Zynga in 2007.

Of course, they've been helped by the massive growth of Facebook, where the games are so popular they've spawned 'fan' pages devoted to complaining about having to watch friends play them.

Facebook, with its 400 million users, is where the vast majority of people play FarmVille and Mafia Wars along with other Zynga titles like FishVille, Vampires, Café World, YoVille and Zynga Poker.

In all, more than 65 million people play Zynga games every day, according to media tracking company Developer Analytics.

Zynga's top title, FarmVille, is played by an estimated 75 million people each month -- roughly equal to the number who have played the classic arcade and desktop game Tetris during its entire existence."