LinkedIn faces challenges by Facebook apps

Rather than starting from scratch, independent software developers are trying to add a professional layer to Facebook - and are hoping that users will accept a less-than-complete separation of the professional and the personal.

When users join BranchOut, the software pulls information from Facebook about their education, current employer and job title, leaving out everything else.

"There are some people I'd prefer not to interact with in my professional career, but I'm still good friends with," said Tom Chevalier, global product manager at Monster Worldwide.

David Hahn, vice president for product management at LinkedIn, said his company's business clients "do not have to put up a 'Help Wanted' sign in the window and see who comes in."

Marini concedes that LinkedIn has command of the professions, but he says that leaves ample opportunity for BranchOut to serve others.

Using a broad definition of "professional" adopted by the International Labor Organization, LinkedIn says there are an estimated 640 million professionals out of a global workforce of approximately 3.3 billion, leaving plenty of room for the site to grow.

[...] the relatively minuscule use of the Facebook apps that venture into professional profiles or networking, he said, is "evidence that users clearly want to keep their professional lives separate."