I think Walter Lippmann covered this pretty well 100 years ago in his book Public Opinion (an excellent book by the way, I highly recommend it). Newspapers get money from the public through a hidden commodity tax by way of advertisements. In order to get this to work, they need to sell their circulation, and the value of the circulation depends on the buying power of those in it. As such, the goal of a newspaper has to be to keep it's target audience happy by giving them what they want:
> Circulation is, therefore, the means to an end. It becomes an asset only when it can be sold to the advertiser, who buys it with revenues secured through indirect taxation of the reader. The kind of circulation which the advertiser will buy depends on what he has to sell. It may be "quality" or "mass." On the whole there is no sharp dividing line, for in respect to most commodities sold by advertising, the customers are neither the small class of the very rich nor the very poor. They are the people with enough surplus over bare necessities to exercise discretion in their buying. The paper, therefore, which goes into the homes of the fairly prosperous is by and large the one which offers most to the advertiser. It may also go into the homes of the poor, but except for certain lines of goods, an analytical advertising agent does not rate that circulation as a great asset, unless, as seems to be the case with certain of Mr. Hearst's properties, the circulation is enormous.
> A newspaper which angers those whom it pays best to reach through advertisements is a bad medium for an advertiser. And since no one ever claimed that advertising was philanthropy, advertisers buy space in those publications which are fairly certain to reach their future customers. One need not spend much time worrying about the unreported scandals of the dry-goods merchants. They represent nothing really significant, and incidents of this sort are less common than many critics of the press suppose. The real problem is that the readers of a newspaper, unaccustomed to paying the cost of newsgathering, can be capitalized only by turning them into circulation that can be sold to manufacturers and merchants. And those whom it is most important to capitalize are those who have the most money to spend. Such a press is bound to respect the point of view of the buying public. It is for this buying public that newspapers are edited and published, for without that support the newspaper cannot live. A newspaper can flout an advertiser, it can attack a powerful banking or traction interest, but if it alienates the buying public, it loses the one indispensable asset of its existence.
Especially relevant today, with the number of advertisement driven companies.
Also from the book, how newspapers will often let erroneous stories die rather than correcting them and angering passionate readers:
> The more passionately involved he becomes, the more he will tend to resent not only a different view, but a disturbing bit of news. That is why many a newspaper finds that, having honestly evoked the partisanship of its readers, it can not easily, supposing the editor believes the facts warrant it, change position. If a change is necessary, the transition has to be managed with the utmost skill and delicacy. Usually a newspaper will not attempt so hazardous a performance. It is easier and safer to have the news of that subject taper off and disappear, thus putting out the fire by starving it.