In case you’ve ever wondered if your favorite game on Facebook is making any money … it is.

Electronic Arts (EA), a major gaming company for game consoles, computers and mobile devices, has decided to enter the social media gaming space in a major way. It was announced today that EA would purchase Playfish, the company behind games such as Restaurant City, Pet Society and more, For $400 million.  The deal is structured as $275 million in cash, $25 million in stock options to help retain current employees and $100 million in earnout bonuses for company targets through Dec. 31st, 2011.

It is estimated that Playfish is currently earning around $75 million a year from traditional advertising, in-game sales of digital items and through offer advertising.

So, the next time you fire up one of those addictive games on Facebook, believe us, you’re helping someone make money.  Sure it looks like you’re not doing anything, but click an add … buy something for your farm … click on one of those offer ads that will give you game items in exchange for doing something, and well that suddenly turns into a multi-million dollar business.  This isn’t to say this is a bad thing, it’s just shocking to see how much all of that really adds up to.

And remember, Playfish isn’t the biggest company in the market, that would be Zynga … anyone want to guess how much they are making per year?