Facebook Inc. became the latest entrant into the online video battle Thursday, opening its Facebook f8 platform to outside developers and partners in an effort to gain ground on social networking rivals.

The move allows third parties to develop functions for Facebook, including video, advertising, and retail capabilities. Part of the system will use the company's own markup language, creatively titled Facebook Markup.

Since News Corp. bought rival MySpace in 2005, Facebook has struggled to keep pace. Last year, Facebook declined a US$1 billion acquisition offer from Yahoo Inc., instead choosing to go it alone in hopes of a better offer or greater solo success. Thursday's announcement could push Facebook more towards becoming a commercial provider of social networking tools, rather than attempting to take on MySpace as a consumer play.

Allowing outside parties to begin selling advertising on Facebook could also help the company to monetize its audience, estimated by comScore Networks Inc. at just over 23 million visitors per month. Self-starting advertisers and retailers could build their own applications or retail functions, saving Facebook the effort while still providing revenue.

The IDG News Service is a Network World affiliate.