As of today, it's finally legal to fly drones commercially

For years, American businesses have been clamoring for the government to roll out a set of regulations for drone technology so that the companies can legally start using them for everything from agriculture to filmmaking to delivering packages. On Monday, an important set of federal drone rules finally took effect across the country -- making it possible for firms to start using drones in a limited manner. Over time, the government will write other rules that will enable the use of commercial drones even more widely. But for now, this marks a huge milestone for the industry, one that's likely to lead to big changes for business and the economy. Here's what you need to know to get up to speed: Most important are the big limitations.