Spot on, Christian. I'd clarify one point: the debate is often misleading when expressed as being about concentration of "ownership". A common conception that flows from this is that there's no reason media owners wouldn't have a diversity of outlets and hence ownership is fine as long as we have a wide choice of media to consume. This is a commonsense conclusion and it misses the point.

The debate is really about diversity of "sources" of news, information and analysis. Generating newsworthy content, which requires correspondents all over the world, is very expensive. It's only economical for any single proprietor to maintain so many of these, and New Media "convergence" is making content production more efficient as, for example, TV reporters also file newspaper and magazine copy, and this copy is repurposed to the Internet and/or syndicated publications. So a single correspondent can provide the content for every report that may be seen on a particular topic - especially when the content comes from remote or high-risk places like Somalia, Iraq or Guantanamo Bay. You often see this in <i>The Australian</i>, which gets nearly all its world news from a few News Ltd publications in the US and UK.

But there's a lot more to those stories than any single report can convey so the public needs a diversity of sources, which is not in Rupert Murdoch's (or any other media owners') financial interest to provide. Maintaining a reporter is an expense; repurposing the content into more pages and broadcasts generates more advertising space and hence is revenue-positive - but does not provide a better service to readers. Hence, media oligopoly is a problem, and New Media developments are making it worse, not better.

All very true but how much will contraction of outlets really limit news diversity, and presumably somewhere at some time a hit on the truth? How much have we and if it goes will we, the majority notice. The old story about they came for the important people but I am not important so I said nought e and so on to my demise.

Chomsky and many others make the point that it is not so much censorship of views or number that limits diversity, as selection for and by a culture that is in general agreement with the established beliefs.
The degree to which this is altered by market forces, I.e. advertising I don’t think has been measured.
The role of individual owner or board is important if one thinks media is about informing the electorate, how important being a much debated topic.
After all one cannot have the multitude of inferior (well they are not rulers are they?) people directing a democratic government. Much better a Murdoch or in fact a coterie of media report on matters of importance giving clear information to the electorate as happened in the run up to the Iraq war (just to name one of many but there are other dramatic and important events and questions so treated).
Pity this information was applaud able only for its inaccuracy and sycophantic regurgitation of the official line. Australia did not escape the contagion.

We could , I.e. the electorate lobby for hanging as penalty for mendacious reporting as happened at the Nuremberg trials, but it would not get far.

We could lobby for an independent advisory group to advise and publish the advice on matters such as war.

We could hope that education will somehow provide enough people who see being informed as necessary to democracy.
Or
We could as we will, have a few informed and concerned giving weight to credentials as a democracy with the remainder adopting the current posture of leaving it to the brass and following sport or whatever.
This will happen. Johnny will be pleased!