Who is an employee and who is a contractor? Uber ruling is opening an enormous can of worms for American businesses and workers.

The California ruling about whether Uber's drivers are employees or contractors spotlights a critical issue for American workers and businesses. Who is an employee these days and who is a contractor? And what does this mean for businesses that employee thousands of contractors? Will they end up paying decades of back pay and pensions to workers previously classified as contractors? What do you think?