Facebook becomes hub for outside software makers

By Eric Auchard

SAN FRANCISCO (Reuters) - Facebook.com on Thursday took the wraps off its highly anticipated makeover from a members-only club into what it hopes can allow it to become a software operating system for all sorts of Internet media.

The college student social networking site, which opened up to users of all ages over the past year, said it has signed up 65 partners, including Microsoft Corp. and Amazon.com Inc., to build Web applications within Facebook.

Other companies building services within Facebook include photo-sharing site Photobucket, multimedia presentation site Slide, music discovery site iLike, new-style instant messaging site Twitter.com and Web-calling companies Jajah and Jaxtr.

Founded in 2004 by then-undergraduate Mark Zuckerberg as a socializing site for fellow Harvard students, Facebook now has 24 million active users and is growing by 3 percent a week.

The company, which operates under the radar of much of the traditional tech industry, is looking to transform itself from a Web site into what Silicon Valley calls a "platform" -- a foundation service on which many other applications can run.

The No. 2 social network site, behind News Corp.'s MySpace, will allow developers to build services that work both inside Facebook's site and on their own independent sites.

"Until now, social networks have been closed platforms. Today, we're going to end that," Zuckerberg, Facebook's 23-year-old CEO, told a gathering of software developers.

Facebook has developed a fanatical following, despite going relatively unnoticed by many users on the wider Web. Half of its users, or 12 million people, return daily to the site to check on what their friends are saying and doing.