Here's a trend you'll be reading more about: part-time "job sharing," not only within firms but across different businesses.

It's already happening across the country at fast-food restaurants, as employers try to avoid being punished by the Affordable Care Act. In some cases we've heard about, a local McDonalds has hired employees to operate the cash register or flip burgers for 20 hours a week and then the workers head to the nearby Burger King or Wendy's to log another 20 hours. Other employees take the opposite shifts.

Welcome to the strange new world of small-business hiring under ObamaCare. The law requires firms with 50 or more "full-time equivalent workers" to offer health plans to employees who work more than 30 hours a week. (The law says "equivalent" because two 15 hour a week workers equal one full-time worker.) Employers that pass the 50-employee threshold and don't offer insurance face a $2,000 penalty for each uncovered worker beyond 30 employees. So by hiring the 50th worker, the firm pays a penalty on the previous 20 as well.

These employment cliffs are especially perverse economic incentives. Thousands of employers will face a $40,000 penalty if they dare expand and hire a 50th worker. The law is effectively a $2,000 tax on each additional hire after that, so to move to 60 workers costs $60,000.

A 2011 Hudson Institute study estimates that this insurance mandate will cost the franchise industry $6.4 billion and put 3.2 million jobs "at risk." The insurance mandate is so onerous for small firms that Stephen Caldeira, president of the International Franchise Association, predicts that "Many stores will have to cut worker hours out of necessity. It could be the difference between staying in business or going out of business." The franchise association says the average fast-food restaurant has profits of only about $50,000 to $100,000 and a margin of about 3.5%.