Amateur radio is guys like me that talk for fun, but have gotten licensed where we had to take a test to prove our technical knowledge, and understanding of the rules that apply to us, there are 3 license classes, each upgrade earns more frequencies (places to talk). Many of the online feeds are limited to storm spotters, but you can hear some ch!t chat in between events sometimes. Lots of times you'll also hear us helping out in a volunteer capacity in times of emergency.
Public safety, is police and fire and EMS and Emergency Management, your first responders; in Indiana most agencies are one one state wide radio system that works a little like direct connect on cell phones so you could in theory have a trooper talk to Indy from anywhere in the state, but it's mostly just around the county or city or state district.
There is also business band, that almost always requires a licenses unless it's low power and on specific frequencies, air band all the traffic with the planes, marine band for between boats; there's CB radio that's a few (40) channels that's unlicensed and if for "personal use" but is about as clear an example of anarchy as you can find from lack of enforcement so it's a bit of everything, or there's FRS and GMRS which is a family radio service that's almost all unlicensed users again for personal use, but there are some businesses grandfathered in to using those frequencies. And naturally the military has presence in different parts of the radio spectrum as well. I've got a link to a colorful chart somewhere that show just how many different frequencies are designated for different uses.
