With more than 232m monthly active users, here are the games that won the online game developer success.
Farmville became an instant hit on Facebook when it launched in the summer of 2009, quickly reaching more than 10m daily active users. The game allows members to manage a virtual farm by planting and harvesting virtual crops, raising livestock and buying extras for their farm using Farmville coins.
There are now more than 30 million virtual farms in Farmville, compared with just two million real farms in the US.
The Telegraph [Slideshow]