Fast-growing social game company Playdom has acquired Metaplace, which failed in its attempt to create a site for user-generated virtual worlds. The price of the deal wasn’t disclosed.

The move is the latest in a spree of acquisitions by Playdom, which is racing to catch up with social game rivals such as Zynga in one of the hottest markets in games. Last month, Playdom said it raised $33 million to fuel its rapid acquisition pace.

The outcome could be a good one for Metaplace, which did a two-step and shifted strategy earlier this year. Metaplace shut down its meta world, which consisted of 30,000 user-created virtual worlds, at the end of December. At the time, founder Raph Koster said the San Diego company was pursuing an exciting opportunity but declined to comment further on it.

Now it’s clear that Mountain View, Calif.-based Playdom wants Metaplace’s talented team to work on social games. Koster and John Donham founded Metaplace in 2006, after leaving Sony Online Entertainment, where they worked on groundbreaking online titles such as Everquest II and Star Wars Galaxies. The company created tools that let users build their own small virtual worlds within a larger virtual world.

But the virtual world craze went out of fashion, and Metaplace never got traction. Instead, it switched to making social games and launched titles such as Island Life and My Vineyard earlier this year. Now, Metaplace’s social game engine will become a key part of Playdom’s unified back-end technology for a variety of games, said David Sobeski, chief technology officer at Playdom. He considers the Metaplace engine to be a competitive advantage, as it will shorten the time it takes to make social games.

These days, I’m hearing that a lot. Social game companies don’t want to create just one game at a time. Their industry is moving so fast that they all need some kind of engine that they can use to churn out multiple titles. MTV Networks, Big Fish Games, Digital Chocolate and others are all launching games that share some common infrastructure. Donham will run the San Diego office, while Koster will do creative game design work with Dan Yue, chief product officer. Jason Hable, vice president of business operations at Metaplace, will move to Playdom’s headquarters to work on making money. Metaplace’s backers included Marc Andreessen, Ben Horowitz, Crescendo Ventures and Charles River Ventures.

Playdom has acquired a bunch of game studios in the past six months. It has more than 130 million games installed on Facebook, MySpace, iPhone and Hi5.

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