At its Google I/O developer conference next week, Google will shed light on technologies such as Google App Engine, for building and hosting Web applications, and OpenSocial, the Google-backed API for social networking.

Other technologies such as the Android mobile application platform also will be discussed.

The conference is to be held in San Francisco from May 28 to 29. Originally expecting 2,000 attendees, Google already had 2,500 people signed up by Thursday evening, said Tom Stocky, Google director of product management.

App Engine will be the subject of some announcements that the company is keeping under wraps until next week. "App Engine is Google's solution for building and hosting Web apps on our infrastructure, and it makes building Web apps easier to scale and easier to get started," said Pete Koomen, product manager for App Engine at Google.

"Here, we've been building Web apps for a while, and we've got a lot of experience in this area," Koomen said.

With OpenSocial, the company will discuss version 0.8 of the OpenSocial API specification, an industry-backed initiative to enable applications to access data on social network sites. The intent is to allow developers to build applications that can access a social network's friends and update feeds. There is an agreed-upon specification for version 0.8, but code for it remains in development.

OpenSocial is infrastructure for the Web, said Kevin Marks, Google developer advocate. Featured in version 0.8 are REST-ful APIs and the ability to access data on a social-networking site when the application is not running in the browser; offline capabilities are enabled.

"We're covering all the different aspects of OpenSocial development from building applications to [making] a social network site into a container for applications, and then there's discussions about how to get your applications you developed to spread within social networks and technologies and tips for that," said Marks.

"What OpenSocial does is it provides a common API for developing social applications," similar to how J2EE provided an API for Java development, said Bob Bickel, CEO at OpenSocial supporter Ringside Networks. Ringside enables Facebook and OpenSocial applications to run on any Web site, serving as a social application server.

For version 0.9 of OpenSocial, a templating language may be added to make it easier to generate HTML without having to write JavaScript code for that purpose, Marks said.

Although backed by companies such as MySpace and Yahoo, social-networking site Facebook is absent from the list of OpenSocial supporters. "Facebook is very welcome to implement OpenSocial, and we're asking and encouraging them to do that," Marks said. A Facebook representative said the company will watch the evolution of OpenSocial and evaluate whether to participate in the future. Facebook has had its own application development program.

OpenSocial is governed by the OpenSocial Foundation, featuring Google and other supporters.

Additional topics to be covered at the conference include AJAX (Asynchronous JavaScript and XML) technologies, such as Google's AJAX APIs and geographic systems.