What Happens If You Don't Sign Up?
Consumer Guide

Business Insider provides some insights. The health care exchange is open for every U.S. resident, but only the uninsured will face penalties for skipping out. If you are enrolled in your employer's health plan or pay for your own plan already, you can keep on keepin' on, although we'd at least recommend shopping around to see if there are more affordable plans out there. 

Kaiser Health News provides a summary of the Affordable Care Act.