When I started blogging, I saw a lot of concern from journalists that blogging would ruin journalism. I wasn't too concerned, because journalism as a practice does not become ruined by diversity - but that was before I considered that while the best practice of journalism might not be changed, the general understanding of journalism might change.
Today we see a lot of "community journalists". Some are quite good and deliver an important service, reporting on topics that are overlooked, ignored or not accessible to others. The P2P net running in China to spread information off the internet about the protests is one example of this. But some are basically just spokesmen for a movement, and should rather adopt the terms "community press agents" or "community PR agents". This because they choose to represent rather than report, and they enter into the dissemination of ideas in order to convince, not to find the truth.
Often these community channels believe they are representing the truth. That is the problem with conviction, it is hard to see beyond it. Traditional journalism is aware of this problem, which is why balanced reporting is such an important concept. This basically means that in order to call something journalism, it needs to represent more than one view. The opposing side must have a chance to respond, or it isn't journalism, it's just channeling one side of an argument.
It is often difficult to get the opposing side to join in a community channel broadcast though, because the other side knows they are entering into a hostile environment. This has nothing to do with knowing they will meet disagreement, and everything to do with knowing they will be called names, ridiculed, and anger the audience of that broadcast. In present-day community activism, that includes, and is not limited to, being investigated by hostile investigators looking to grasp at anything that looks like an error, misrepresented in chat-rooms and on blogs, called names, having their emails attacked and their accounts hacked, and receiving threats starting with vague "making life unpleasant" going through phases of "we will ruin their lives and take away their careers" and up to rape- and death threats. These are very efficient silencing techniques, and journalists who work with areas where this can happen need to be very smart and very trustworthy.
This is the reason why traditional journalism contains the idea of "protecting the sources". Journalists have gone to jail in order to protect their sources, and that is why they can break open some astounding cases. The source needs to feel it is safe to offer up information.
The source also needs to believe that the information they offer up will be treated fairly. If the journalist cherrypicks the few items in the information that suits their angle, and is not ready to acknowledge when either side has a fair point, then the journalist will become a microphone stand for the loudest and most popular voices in his or her community, and not an investigative fair reporter. This (treating the opposition fairly) is rarely happening in community channels, because they are economically and socially tied to their audience. When they live directly off donations or clicks on their shows, allowing topics that will unsettle or perhaps even disperse the audience will not happen.
Quite the opposite, the community channel sees itself as defending, protecting, and fighting the good fight for their followers. The hosts of these channels may even feel that their cause loses if they have to admit that they may have been wrong, and so they will fight bitterly to the very end to support their cause. That is quite all right, as long as we agree on what that actually is. It is not journalism, it is PR, or even more frequently, propaganda, when the fact checking is flawed and they keep searching only for confirmation of their own idea.