
Microsoft purchased a 1.6 per cent stake in Facebook for $240m in October, valuing the site at US$15bn.
Facebook opened up its interface to developers in May, allowing users to create a wide array of applications that can be installed into a user's profile. MySpace launched a similar feature in October.
Chris DeWolfe, chief executive and co-founder of MySpace, said: "Our partnership with Google allows developers to gain massive distribution without unnecessary specialised development for every platform.
"This is about helping the start-up spend more time building a great product rather than rebuilding it for every social network. We are pleased to collaborate with Google to establish a landmark standard for social applications."
As a member of OpenSocial, MySpace and others will provide guidance on the platform standards, which are designed to evolve through contribution from the open source community and as new features are developed by various partners.
Based on HTML and JavaScript, the standard OpenSocial APIs will give developers access to the data needed to build applications across all participating sites, rather than creating separate programs for each one.
"OpenSocial will benefit Xing members by giving them access to more social applications and more features on the Xing platform," added Lars Hinrichs, founder and chief executive at Xing.
"Members will now be able to choose from a pool of new business applications, from connections to CRM systems to project management tools and to-do lists.
"This common set of APIs also complements our development work on the Xing API and keeps us at the forefront of innovation in social media."
Other companies to sign up to the OpenSocial community include Engage.com Friendster, LinkedIn, Oracle, Plaxo, Salesforce.com and Google's own social networking site Orkut.