Research by The Human Capital Institute indicates that one-third of the U.S. work force is now composed of freelancers, also known as contract workers. And the institute says the pool of these workers, who often are part-time, is growing at more than twice the rate of the full-time work force.

According to the Bureau of Labor Statistics, freelancers were one of the few groups that continued to see job growth throughout the recession and the slow economic recovery. The bureau adds that this trend has been building for a number of years. From 1990 to 2008, the bureau says the number of contract positions grew from 1.1 million to 2.3 million and includes a larger share of workers in higher-skill occupations.

Another labor bureau study found that about one in nine American workers is self-employed. It's not just entry level, or even midcareer, job hunters who are joining the freelance world. Increasingly, top-level managers and executive teams are being shaken from established bureaucracies, replaced by temporary CEOs and troubleshooters brought in for their expertise in solving specific problems.

Corporations are sitting on piles of cash rather than investing in new employees to replace the ones they downsized in cost-cutting moves. Employers are waiting to add to permanent payrolls until they're more certain about the recovery, their future taxes and health care expenses.

Furthermore, it's simply easier to bring in or release temporary freelance workers as needed. There's less expense in hiring or firing and less worry about employment-related lawsuits. To underscore this trend, Freelancer.com, which claims to be the world's largest outsourcing marketplace, connecting small business with freelancers from around the world, says it has now registered two million professional freelancers.

Freelancer.com recently acquired the New York based outsourcing company LimeExchange. It says the two million freelancers and small businesses are from 240 countries, regions and territories worldwide. The largest country represented is the United States, with over 21% of users. Second is India with 19%.

To date over 890,000 projects have been posted on Freelancer.com, from projects as simple as designing a website or a logo to designing a fully functional dune buggy. One project called for the composition of a Rap Song to help Chinese students learn English. Each gig only pays a few hundred dollars and the average is under $200. Still, freelancer.com claims there are some who earn hundreds of thousands of dollars.