Employers have long faced difficulties classifying workers as independent contractors in more traditional industries.

The on demand economy is growing — fast.

This type of commerce, largely driven by tech start-ups, allows consumers to quickly and easily buy goods and services with their computers, tablets and smartphones. Dinner can be ordered online; a car ride is available through an app; house cleaners can be hired in minutes; and groceries can be ordered without leaving the couch. Snoop Dogg is even getting into the action as an investor in a delivery app for medical marijuana.

The speed of delivery is possible because a fleet — literally or figuratively — of contract workers is available to provide these goods and services 24/7. These workers have the flexibility to accept many jobs per day as a primary source of income, or just a few per week as a secondary source. This model creates a fluid but deep pool of workers who are classified under the law as independent contractors. These workers may freely pick and choose when and where they perform work for these online or app-based companies. [Read More from Workforce]