Modern public broadcasting is typically a mixed commercial model. While the BBC was originally funded based on fees charged to every user of a television, the ABC and CBC have always relied on a subsidy from general revenues of the government, and more recently advertising revenues, making them competitive with commercial broadcasting. Some argue that this dilutes their mandate as truly public broadcasters, who have no commercial bias to distort their presentation of the news.
In the United States the Public Broadcasting Service, PBS, operates on a mostly viewer-supported basis, with commercial sponsors of specific programs, who are thanked but cannot run ads on the air.
A key advantage of public broadcasting is that it can rely on stable management and policies to attract and develop journalistic talent. This tends to make public broadcasters worldwide particularly trusted for reporting news. Even in the United States where there is far more competition for top news anchors, journalists, hosts and commentators, some of its programs, e.g. the MacNeil-Lehrer Newshour, were widely respected and could attract important people to comment on the issues of the day. Those guests could in turn count on a commitment to balance, and perhaps also more educated questions, which assured them they would not be turned into a public spectacle for the sake of ratings (always a risk in any TV or radio program).
Another key advantage of public broadcasting is that a cultural policy (an industrial policy and investment policy for culture) is relatively easy to implement. For instance the Canadian government commitment to official bilingualism creates stable work at the CBC for translators, journalists who work in French in English regions of Canada, encourages production of cross-cultural material. Some, e.g. Quebec separatists, argue that this is also a policy of cultural imperialism and assimilation. However, this is a criticism of the policy, rather than of the cultural methodology. In the UK, the BBC has also taken a strong stance in favor of multi-culturalism and diversity: many of its on-screen commentators and hosts are people of colour.
For those who oppose cultural policy on principle, of course, the above arguments are strong arguments against public broadcasting. However, even those who object to having 'culture shoved down their throat', rarely object to being exposed to pop culture, law presented as if it were truth, militarism and identification with 'our boys' etc., all manner of culture bias, and consumerism in the form of advertising itself. In public broadcasting, these things can be controlled, or limited, or at least openly discussed. Some will say lack of a cultural policy is a policy in itself.
An interesting example of this balancing role is the use of the word "terrorism". While commercial broadcasters often use the word as if it were a category one could observe directly, public broadcasters are forced by their very mandate to justify their use of the word - the BBC at one point claimed it would label no one a "terrorist" as they considered it a political term. Throughout the IRA crises, the BBC steadfastly referred to "the IRA", "Republican forces" or to "militants". They avoided the term "terrorist" and even "extremist".
Most believe that some public broadcasting, and also some pirate broadcasting, provides a necessary counterweight to the commercial media. Advocates of deliberative democracy, which requires much 'air-time' and 'feedback' and access to public figures to work, usually consider public broadcasting to be an absolute necessity to the maintenance of a complex modern technological democracy.
Whether one likes it or not, in most nations, public broadcasting is all there is. Where commercial media is allowed at all, it usually is seen as an avenue for the presentation of commercial products that few in the population can afford, and a cultural policy of 'invasion'. Public broadcasting sometimes serves simply to put voices or languages on the air that would otherwise be completely ignored, and, perhaps due to a lack of voice, obliterated. To the degree that rumours and hatred can be dispelled by diligent public broadcasting, it can be seen as a public good. Where it is used to amplify hatred and fear, as dictators often use it, it can even lead to genocide.
Accordingly, public broadcasting must probably be managed as carefully as any nation manages its police or military forces. The ability of electronic media to mobilize and motivate the public to a common cause is profound, and its abuse is probably as serious as abuses of force.
See also: commercial broadcasting, pirate broadcasting, radio