It looks like social game publishers like to play together. Zynga, maker of FarmVille and other popular Facebook games, has purchased Newtoy, maker of We Rule (with Ngmoco), Words With Friends and Chess with Friends for mobile. Zynga plans to keep the Texas studio open, rename it “The Zynga With Friends Studio,” and keep the game releases pumping. The terms of the deal have not been disclosed.

“Zynga is committed to providing the best of breed mobile game experience and we expect The Zynga With Friends Studio to deepen our bench of seasoned veterans and broaden our scope of mobile game development,” said David Ko, senior vice president of mobile at Zynga. “The mobile industry is still in its infancy and we’re excited about the opportunity ahead of us.”

Newtoy (if we’re still allowed to call it that), was founded in 2008 and has focused on creating social games for the iPad, iPhone, and iPod Touch. Its Games With Friends franchise is one of the most popular on the iOS platforms.

Zynga continues its road toward social game domination with this purchase. The company has been quite active lately, launching games on Yahoo, partnering with AMEX, and preparing to release its first Android game, Zynga Poker. Its sequel to FarmVille, titled CityVille, also just rolled out to Facebook users.

215 million people play Zynga’s addictive, free games each month, more than 20 times the number of gamers who play Call of Duty: Black Ops on a regular basis, one of this year’s biggest console titles. Do you play Zynga games? FrontierVille, FarmVille, FishVille, PetVille, CityVille, YoVille, Mafia Wars, Cafe World, Zynga Poker, or Treasure Isle? What do you think of them?