Facebook CEO Mark Zuckerberg is the youngest-ever self-made billionaire on Forbes magazine’s annual billionaires list. Zuckerberg, 23, who has an estimated net worth of $1.5 billion, founded Facebook in 2004 from his dorm room at Harvard.

While high school and college students make up the core group of Facebook users, it’s capturing the interest of more people 35 and older — particularly those in business.

“This is a key market for Facebook. When you think about the 26 million small businesses in the United States alone, there’s an upside to that,” says Brian Moran, president of the Moran Media Group, a New Jersey publisher of magazines and online materials for small businesses.

Facebook works like most social networking sites. The main objective is to build your network. For entrepreneurs, this network can become a resource they can tap for ideas, for help solving business challenges, and to market products and services.

But unlike LinkedIn, the preferred networking site for business professionals, Facebook's more casual approach can make someone looking to do business feel uncomfortable.

"The concern for people is, I don't want to mix business with personal," says Moran, whom I met on Facebook through a query I posted seeking people using Facebook as a business tool. "Social media is like the Wild West. People are moving online en masse. But they're trying to figure out what works for them."