Electronic Arts Inc. (NASDAQ:ERTS) has closed an acquisition deal with Playfish. Playfish is a company that designs games for social networks such as Facebook. EA is spending $400 million to buy out Playfish. Of the $400 million, $300 million will be given upfront and the additional $100 million will be paid as an earn-out. Rumor has it that EA was considering buying out Playfish competitor Zynga Inc. too.

This past September about 250 million people played games on Facebook. One of Playfish’s most popular games called Pet Society has over 20 million active users. Playfish was started by Kristian Segerstrale and Sebastien de Halleux. Playfish raised venture capital from Accel Partners and Index Ventures.