Last week it missed out on the chance to buy a stake in Facebook with the founders choosing instead to do a deal with Microsoft.

"Facebook-fear"

Google said that around a dozen social network partners had signed up to the system, including business site LinkedIn, Friendster and Google's own social network Orkut.

Developers already onboard include Flixster, iLike and RockYou.

Unlike Facebook, OpenSocial allows developers to write in normal javascript and html with only minor adjustments needed for the code to work on its platform.

According to blog TechCrunch the plan is likely to be a big hit with developers as well as Facebook's rivals.

"Developers have been complaining non stop about the costs of learning yet another markup language for every new social network platform, and taking developer time in creating and maintaining the code," wrote TechCrunch's Michael Arrington.

He is impressed by the number of social networks that have signed up so far.

"Facebook-fear has clearly driven good partners to side with Google," he wrote.

Technology writer Om Malik observed: "OpenSocial attacks Facebook where it is the weakest (and the strongest): its quintessential closed nature."