Prepare for some headaches. Or possibly shrugs. The FAA wants every American to register every drone that weighs more about half a pound, or 250 grams. And they have decided that the registry will be retroactive.
If you already have a drone or have had one for years, and it weighs more than .55 pounds, you have been ordered by the FAA to prepare to register your information and pay $5 to the FAA. The $5 covers any number of drones you may own, and if you register within 30 days of the FAA's system opening up (it begins on Dec. 21), the $5 will be reimbursed.
If you refuse to register your drone to the FAA, their FAQ wastes very little time telling pilots they could face civil fines of up to $27,500 and criminal penalties of up to $250,000 and imprisonment for three years. I'd ask how the FAA intends to prove that individuals who purchased a UAS before the registration system was implemented would know about its existence, but that would assume the government would care about any such thing.
The weight requirement eliminates most toy drones that fit in the palm of the hand, and the FAA put together a page showing examples of some of the smaller drones that will be exempt from registration. Any drone that is likely to be used for filming or surveillance will probably fall on the heavier side of the cut-off, though there are some exceptions in some of the smaller drones.
Of course, technology being what it is, it's easy to imagine this new rule being just another incentive for drone manufacturers to find ways to make their products smaller and smaller so as not to force customers into a federal registration regime.