The legislation covering drone registration was part of a wider $700 billion National Defense Authorization Act, so it is unlikely that drones have been particularly targeted by the government. All drones between 0.55 and 55 pounds are required to be registered. The full rules can be found on the FAA’s website.
In May, the initial ruling was shot down by the US Court of Appeals, who said the registration rule violated the FAA Modernization and Reform Act, which states the FAA "may not promulgate any rule or regulation regarding a model aircraft." With the registration being overruled, the FAA had to turn back to the drawing board to cinbsider the best way to regulate the nation’s airspace as drones grow in popularity. Almost 900,000 people had registered their drones under the first ruling, and the FAA expected over 2 million consumer drones would be sold this year in the US alone. The FAA has welcomed the return of the rules, citing the privacy and safety benefits of registration.
References: TechCrunch cnet