Google, MySpace, and Yahoo on Tuesday said they have agreed to form a non-profit group that would govern the development of a standard application programming interface that developers could use in building software for supporting online social networks.

The three Internet companies expected the OpenSocial Foundation to launch in 90 days, and asked for others in the industry to rally behind the OpenSocial API, which was developed by Google to foster development across emerging social-network development platforms.

MySpace, which accounted for three-quarters of the Web traffic to social networks in the U.S. in 2007, and its second-place rival Facebook have been opening up their platforms to third-party developers in an attempt to add services that may attract advertisers and keep subscribers on the sites longer.

While Facebook is offering its own proprietary tools, MySpace and other social networks, including Google's Orkut, Hi5, Friendster, Imeem, LinkedIn, and Plaxo, have agreed to adopt the OpenSocial API, which connects to Web apps built in JavaScript and HTML.

Google, MySpace and Yahoo have agreed to contribute technology to the OpenSocial Foundation under a "no assertion covenant," which means they won't seek to enforce any patents on the intellectual property, representatives told reporters during a teleconference. All companies joining the foundation would be expected to contribute technology under the Creative Commons copyright license.

The foundation is expected to launch by July 1 as an independent non-profit entity with a formal intellectual property and governance framework. The group is expected to provide operational guidelines around technology, documentation, intellectual property and other issues. Future direction of the foundation would be determined by the membership.

A foundation Web site has been launched as the portal for the community. The site includes the latest specifications and links to other resources. In addition, a second site has been launched for people who wish to signup and join the effort.

During the teleconference, executives acknowledged that use of the OpenSocial API would not guarantee that applications built for one social network would transfer unchanged to another site. Some modifications would probably be necessary to take advantage of unique services offered by each site.

However, use of a core API is expected to cut down development time from "months to hours," Joe Kraus, director of product management for Google, said. "We think we're off to a great start (toward interoperability.)"

Missing from the list of OpenSocial supporters is Microsoft, which is in the midst of a takeover attempt of Yahoo. The proposed acquisition is pending, and it's unclear what affect a successful takeover would have on Yahoo's involvement with the OpenSocial group.