The farm just isn't exciting as the city.

CityVille, the hit social game from Zynga that allows users to build a city from the ground up, now has over 100 million monthly active users on Facebook. That user base is all the more impressive when one considers that the game hit that mark a little over one month since its release.

CityVille's meteoric rise has made FarmVille, another wildly popular title on Facebook, look, well, desolate. That game has over 57 million active users, according to its Facebook page.

Zynga's CityVille success has helped the company maintain its leadership position in social gaming. According to its Web site, it has over 215 million monthly active users and more than 50 million daily active users.

In other social-gaming news, RockYou announced that it has acquired developer Playdemic. The terms of the deal were not disclosed, but RockYou said the developer, which is best known for its Facebook game, Gourmet Ranch, will operate independently.

Although Gourmet Ranch has just half a million monthly active users, RockYou has garnered major followings for its games. The company has over 200 million monthly unique visitors and over 15 billion "monthly global impressions," it said. Its most notable game is Zoo World, which according to its Facebook page, has nearly 9 million monthly unique users.