Yahoo agreed to join rival Google’s OpenSocial platform, which aims at building an infrastructure for the social web, as Google described it. Through the OpenSocial, platform, developers will be able to create applications for social-networking sites. The platform was launched last November, and MySpace is already a member.

“OpenSocial has been a community-driven specification from the beginning,” said Joe Krauss, Director of Product Management with Google. “The formation of this foundation will ensure that it remains so in perpetuity. Developers and websites should feel secure that OpenSocial will be forever free and open,” Krauss added.

This association appeared as a surprise considering the known rivalry between Google and Yahoo, but, together with MySpace, the three said they were planning to ensure neutrality and longevity for OpenSocial and as founding members to offer developers the potential to connect with over 500 million people worldwide.

“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 Wade Chambers, Vice President Yahoo! Platforms. “Our support builds on similar efforts with the OpenID community and will expand the opportunity for developers and publishers to benefit from an open and increasingly social web.”

MySpace also welcomed Yahoo! as an important addition to the OpenSocial network, stating that this alliance will provide developers with the necessary tools to make the Internet faster and ‘foster more innovation and creativity.” The organization will be created within the next three months.

With the help of OpenSocial, developers will be able to create applications to access social networks and update feeds, and with the help of a common API, they will also be able to make them available to users. This movement looks as a response to Facebook’s own open system that allows developers to create applications on the Web.