Burda lives a busy, productive life, one that would make politicians touting the promise of the American dream gush during campaign rallies. The Ukrainian son of a dentist (father) and a mechanical engineer (mother), Burda and his family moved to the United States in the early 1990's. He earned an MBA from St. Joseph's University and speaks three languages fluently. He does financial planning for aerospace and defense giants like Boeing and Lockheed Martin. On the side, he started a non-profit to provide consulting to small businesses. He and his wife are expecting a baby boy any day now.

So why does Burda give LinkedIn — and fellow users of the service, many of whom he couldn't identify if they sat down next to him at a coffee shop — so much attention? Quite simply, he likes helping people.

"For me, it's a hobby and a passion," he says. "They call me the Mother Teresa of social networking. I help people find jobs or secure VC [venture capital] on LinkedIn. There are plenty of places that charge all this money to use their job tools, but I help people without seeking anything in return. I firmly believe the karma comes back to you eventually."

Burda's pay-it-forward philosophy is shared by his fellow "open networkers," an increasingly significant group of LinkedIn users who accept the majority of invitations to connect on LinkedIn, no matter whether they know the person or not. Open networkers also help other people connect with one another by introducing them online, even if they don't know either person in any personal or professional capacity. This approach runs counter to the wishes of LinkedIn, which publicly encourages people to connect only with people they know. During the past couple of years, LinkedIn has even taken measures within the design of the service to curtail the practice of open networking.