One of the neat things about public broadcasting is the many different levels on which it operates. The distinction which separates public broadcasting from other types is the way it airs its programs and where the funding comes from. While cable companies will support channels through service fees as well as the funds made from advertising on their programs, public broadcasting comes from public funds.
You would think this fact would limit the scope of public broadcasting somewhat, in that you would need a large umbrella organization to oversee it all; however, that is not the truth. In Canada, public broadcasting can be run from the national, provincial, regional, or local levels. Let's look at some examples of each.
On the national level, of course, Canada has the Canadian Broadcasting Company. This company operates four television channels, and four radio channels. While the radio channels have no advertising, anyone watching the CBC knows that you may see companies marketing a wide variety of goods and services on the channel. The ads which appear are strictly regulated, and include a certain percentage of Canadian content.
The national networks also operate at the local level. Much of their programming is consistent across every station for many time slots, but there is also an allotment of airtime for the local station's own programming. For example, CBC will nationally air a prime time show across all its stations, so the viewer in Ontario will see Grey's Anatomy at 8:00 on Thursdays while someone in BC watches it at 5:00 pm. But at 11:30 each evening, for example, the Vancouver viewer and the Toronto viewer will each watch his own local news broadcast. It's no different from the setup of many companies that serve customers across Canada - head office handles the major policy decisions while the individual branches customize their offering to meet the needs of the local market. Re/Max is a great example of a huge national organization (www.remax.ca) whose services are provided by very locally focused representatives (e.g. Gary J. Sullivan, independent Realtor).
Six provinces also operate public broadcasting television stations. These typically air programs geared towards education and knowledge enhancement -- National Geographic programs on the field of our environment for example. These stations tend not to have any commercial advertising at all, although they do market their own programs in packaged form.
On the regional and local levels, usually only the major cities can afford to operate their own public channels. Again, these may see funds coming from local businesses or governments, according to the budget and application structure. These stations can be quite useful for residents, who are looking for weather information or traffic reports as well as local news and community programming.
All communities also have a local only access channel, which is part of the stipulation provided in commercial company contracts by the CBC. This channel is specific to each community, and runs locally based shows.
Finally, on the very smallest of scales, is public broadcasting on the campus level. This includes radio programs run out of colleges and universities all across the country. These campuses often cannot afford their own television stations, and opt to operate on the FM dial of the radio instead. Again, they are great sources for those looking for strictly local information.