Friendster fully launched its developer program with a directory of more than 180 applications Tuesday. Popular widget developers RockYou, Slide, Clearspring, Imeem, Jangl, and gBox were the first developers to participate in the social-networking site’s pilot program put together in October.

“This is a great opportunity for the entire ecosystem of widget and application companies to plug into Friendster,” said David Jones, vice president of marketing at Friendster.

Friendster’s widget courting comes after the official launch of the Facebook Platform back in May. Facebook’s addictive, seemingly endless widget options have helped it replace MySpace as the social network to beat.

Similar to Facebook, Friendster allows third-party developers to display ads anywhere within their applications and keep all revenue. “Developers have complete freedom to monetize,” Mr. Jones said.

Mr. Jones added that Friendster has created an entirely open platform that includes APIs that are compatible throughout the industry. This allows existing applications on other social networks to be easily imported to Friendster. The site has also signed on to support Google’s OpenSocial APIs when OpenSocial is “completed and secure.”

Every social network will open up to third-party development in 2008,  Forrester Research analyst Jeremiah Owyang said.

In a sense, widgets are creating their own networks. “This is a great opportunity for advertisers,”  Mr. Owyang said. Rather than advertising on individual social networks, brands that advertise on popular widgets can reach multiple audiences at once.

“These things [social networks] are just platforms …Widgets will go where the people are,” Mr. Owyang said.

Formerly the top online social network, Friendster has watched its popularity dwindle in the United States while Facebook and MySpace have risen to dominance. However, the site has attracted 41 million registered users in Asia and 56 million registered users worldwide. With the hope of increasing its international audience, the site has created Chinese, Japanese, South Korean, and Spanish-language versions over the past few months.

“Friendster’s user base is different than other social sites,” said Jeff Roberto, Friendster’s director of marketing. “By plugging into Friendster, these developers are gaining an entirely different user base.”