Google has upgraded its OpenSocial platform with a new REST (representational state transfer) API for applications that need to tap back-end servers for data and functionality.

This capability had been eagerly awaited by developers creating OpenSocial applications, particularly because having the REST API (application programming interface) is considered key for mobile applications.

Version 0.8 of OpenSocial also enhances the platform's JavaScript API, Google announced Wednesday at its I/O developer conference.

"This represents the next evolution of the OpenSocial API, which was scoped, specified and built via an open process run by the community," wrote Google product manager Dan Peterson in the OpenSocial blog.

OpenSocial is a project that provides a set of basic APIs so developers don't have to fully re-write an application to have it run on each social-networking site. The JavaScript API modifications are detailed in version 0.8's release notes.

In a related I/O announcement, Google said that MySpace is adopting its Gears technology for storing data from Web applications locally in a browser for offline access.

Specifically, MySpace will use Gears in the e-mail service it provides to its social-networking site members. To date, this is the largest implementation of Gears outside of Google and the first time MySpace has made available functionality for its users to search and sort mail.

According to MySpace, its members send an average of 170 million mail messages every day using the site's mail system. Through its local storage capability, Gears will allow them to search and sort their mail rather than having to manually scroll through their messages.

In addition, Google announced that popular blog-publishing service WordPress is also using Gears to let its users manage their blogs offline, and that Gears now also supports Apple's Safari browser and version 3 of the Firefox browser.

Also at I/O on Wednesday, the company released an API and a browser plug-in for its Google Earth mapping application. "[Developers] can now use the Earth as their canvas and apply their creative vision to a geographically rich, 3D environment, leveraging the same technologies we use in the desktop Google Earth client. For consumers, this means that they will soon see Google Earth in many more places around the Web -- perhaps even their favorite Web site," Google said in a statement.