Update 9/2016 – Peter Sachs – Drone Law Journal: If you are confused about how to legally operate a model aircraft, it’s not your fault, but the FAA’s fault. The new FAR Part 101 is confusing, and has already resulted in controversy.
In a nutshell, to fly a model aircraft under Part 101, you must:
 be operating a model aircraft;
 abide by all of Section 336 of the FMRA of 2012;
 operate within a community-based set of safety guidelines and within the programming of a nationwide community-based organization;
 not endanger the safety of the national airspace system; and
 register yourself as a model aircraft owner if, based upon weight, it is required to be registered.
All of  through  above is discussed in greater detail below, but it is important to understand that all of the criteria of Part 101 must be met in order to operate under it. If any of the criteria of Part 101 is not met, you are not operating under it, and must instead operate under Part 107; under a Section 333 Exemption; under a Public Aircraft Certificate of Authorization or Waiver; operate indoors only; or not operate at all.
Read the full breakdown on the Drone Law Journal.