Wikipedia
OpenSocial is a public specification that defines a component hosting environment (container) and a set of common application programming interfaces (APIs) for web-based applications. Initially, it was designed for social network applications and developed by Google along with MySpace and a number of other social networks. More recently, it has become adopted as a general use runtime environment for allowing untrusted and partially trusted components from third parties to run in an existing web application. The OpenSocial Foundation moved to integrate or support numerous other open web technologies. This includes OAuth and OAuth 2.0, Activity Streams, and Portable Contacts, among others.
It was released on November 1, 2007. Applications implementing the OpenSocial APIs are interoperable with any social network system that supports them. At launch, OpenSocial took a one-size-fits-all approach to development. As it became more robust and the user-base expanded, OpenSocial modularized the platform to allow developers to only include the parts of the platform it needed.
On 16 December 2014 the W3C issued a press release, "OpenSocial Foundation Moving Standards Work to W3C Social Web Activity", that OpenSocial would no longer exist as a separate entity and encouraged the OpenSocial community to continue development work through the W3C Social Web Activity in the Social Web Working Group and Social Interest Group. The OpenSocial Foundation stated that "the community will have a better chance of realizing an open social web through discussions at a single organization, and the OpenSocial Foundation board believes that working as an integrated part of W3C will help reach more communities that will benefit from open social standards." On 1 January 2015, opensocial.org began redirecting all page requests to https://www.w3.org/blog/2014/12/opensocial-foundation-moves-standards-work-to-w3c-social-web-activity/.