In the shadow of Facebook, the leaders of professional networking, are waging a fierce battle and some are preparing their IPO. Viadeo started the war by opening an office in San Francisco in March 2011, Linkedin responded by launching their activities in France. Xing, smaller in size than the other 2 leaders, is stable in its German territory and Spain after acquiring eConozco and Neurona in 2007.

The 3 players are seeing their worldwide growth based on global bad economies and high unemployment rates and job seekers.

But newcomers like BranchOut might spoil the party, counting on the 600 million Facebook users to create their niche network. You can simply sign in using your Facebook credentials, where it will pull your professional information then ask you to pick friends with whom you would like to work.

Branchout launched in January 2011 with 10,000 users, early March the number of users went up to 435,000.

On a separate note, when networking websites, social or professional, publish their users figures, I always wonder about the number of “sleeping accounts” or users having multiple accounts for a reason or another, a fact that no one, mention almost anything about it.