Two months after Google launched its social network, Google+,  Facebook has gone on the attack. Facebook director of game partnerships Sean Ryan claimed that Google had emulated aspects of Facebook, "which is what they have the right to do".

He was referring to the way the companies make money from casual online games like Farmville and Words With Friends. Players pay for play time or virtual goods within the games, and the social networks take a cut of the sales. Currently, Facebook reportedly takes 30 per cent from game developers, whereas Google takes just 5 per cent.

But Ryan argued that Google's gaming foray was like McDonald's recent efforts to compete with Starbucks. He said that Google is offering five per cent because it does not have any users. If it had a lot of users it could screw games developers for more, we guess.

Google+ has 25 million registered users and has a long way to go before it catches up to Facebook's 750 million. However it is clear that Facebook is a little nervy about its new rival.