The block's new Big Bad

Yahoo has announced it will support Google's OpenSocial initiative, reports Mediaweek.

The decision followed assurances that Google would cede some of the control it exercises over the initiative. Yahoo was previously concerned that its chief rival in the search engine/advertising space was too powerful a force.

OpenSocial seeks to spark the development of apps that can be used across all social networks. The OpenSocial Foundation, a managing body consisting of major networks — like Google, MySpace and now Yahoo — will mandate the creation of guidelines and standards for cross-platform development.

Other social networks committed to OpenSocial include LinkedIn, AOL's Bebo and Plaxo. imeem, which just opened its back-end, eventually plans to follow suit.

Others, notably Facebook and Microsoft, continue to hold out. But even without their participation, OpenSocial-agnostic applications are already assured an audience of at least 500 million online users worldwide.