Salesforce.com executives and Sandberg showed off how a recruiting app made on the Force.com platform could be embedded into a Facebook page. The app leveraged the social aspects of Facebook to determine what "friends" on the service might be a leading candidate for a job listing.

Such an example shows how business focused application can use Facebook's "social graph," what Sandberg and the company's CEO, Mark Zuckerberg, (in his public appearances) refer to as showing the connections between friends, family and colleagues.

Facebook, which has nearly 28,000 applications on its platform, has not generally been focused on enterprise or productivity. As Sandberg noted during her part of the keynote, Facebook apps have focused on games, sports, music, and advocacy.

"We think there is more a more for a need for productivity and enterprise apps," Sandberg says. "You can build it on force.com and run it on our platform. We think this partnership is a really exciting step."

Last week, LinkedIn, the social network for professionals, launched a very focused application platform that brought nine applications to users. Analysts called it a departure from the playful, game-like applications of Facebook.