Google plans to launch an open development platform for social networking site applications on Nov. 1, the New York Times and several other sources reported Wednesday.

The project, called OpenSocial, will introduce a common application programming interface developers can use to create applications that will work on any participating social network site. OpenSocial is expected to launch at a party at Google's Mountain View, Calif., headquarters on Thursday.

The New York Times says it learned about OpenSocial from people briefed on the matter, and later confirmed it with the company.

Participants are reported to include Google's social network, Orkut, business networking site LinkedIn, business software maker Salesforce.com and enterprise software company Oracle. Other social networking sites rumoured to be involved are hi5, Friendster, Plaxo and Ning. Reports say these sites have a combined 100 million users, more than double the size of Facebook.

The move will open up a market previously cornered by Facebook, which opened its service to outside developers in the spring. Since then more than 6,000 programs, ranging from games to photo, video and music applications, have been built to run on the site. These programs are encoded with a special markup language that makes them unusable on other networking sites.

With OpenSocial, developers would be able to use normal javascript and html, and applications could be picked up by participating sites across the web.

The new platform is "compatible across all the companies" an insider told the New York Times.

"It is going to forestall Facebook's ability to get everyone writing just for Facebook," said the source, who requested anonymity because he was not authorized to speak on behalf of the OpenSocial group. "Facebook got the jump by announcing the Facebook platform and getting the traction they got. This is an open alternative to that."

It has also been reported that the developers of some of the most popular Facebook applications, such as iLike, Flixster, RockYou and Slide, will tailor their programs to run on the sites participating in OpenSocial. That announcement is expected during the Thursday-night launch party.

After the launch, the third-party developers will reportedly have immediate access to social network information and a live developer sandbox on Orkut.