San Francisco (CA) - Three online giants are now working together on Open Social, an open online platform for social networking. It is the first major joint project for Yahoo since its torrid acquisition attempt by Microsoft.

The Open Social initiative was created by Google back in November, with the goal of making an easily accessible set of application programming interfaces (APIs) for social networking, thereby having a more even playing field for everyone.

Google signed on Myspace right away. The addition of Yahoo in the team gives it a significantly bigger boost.

"Yahoo believes in supporting community-driven industry specifications and expects that OpenSocial will fuel innovation and make the Web more relevant and more enjoyable to millions of users," said Yahoo VP Wade Chambers in a statement.

Google product manager Dan Peterson wrote in the company's official blog that Yahoo signing on will bring additional resources for developers, and will encourage others to come on board.

Google's Joe Kraus said in a conference call today that over 200 million users would be reached by the Open Social program. The program will be community-governed and open to any developer that wants in.

With Yahoo now part of the massive group, the project has decided to become a complete non-profit organization, which is set to be fully authorized by July 1.

In addition, Google has launched opensocial.org as a main "hub" for all information about the project.

Peterson added, "Welcome, Yahoo! We look forward to growing the social web together."