By and large, most journalists don't criticize each other. It's probably a mixture of professional courtesy and ideological agreement (as the media's incessant criticisms of the Fox News Channel show). Still, as much as we like such media self-scrutiny, it is probably best if the publications doing it try to make sure that they aren't engaging in the behaviors for which they criticize others.
For instance, the New York Times recently criticized the Washington Post for running an article written by the Fiscal Times, which quoted as its primary source an individual from the Concord Foundation, without disclosing that Peter Peterson, chief financier of the Fiscal Times, is also a co-founder of the Concord Foundation (h/t nytpicker).
The article highlighted calls from a number of groups, including the Concord Foundation, for a commission to look into ways to reduce the national debt. The Times's coverage of the issue characterized the Fiscal Times as having a "relatively narrow focus on issues that are also pet causes of its sponsor"--i.e. balanced budgets and restrained government spending.
A mere four days after the Times published its mild criticism, however, it too engaged in a similarly shady instance of non-disclosure.
The paper published a book review in its Chicago edition written by the editorial staff of the Chicago News Cooperative. The review, which discussed in glowing terms the book “The Great American University” and used the book's author as its primary source, failed to mention that the book's editor is also the chairman and co-founder of the Chicago News Cooperative.
So while the Times made a valid criticism in noting that the Post had published an article written by a third party that served the interests of that party's officers, so too did the article the Times ran tout a book in which a CNC executive has a financial stake.
Newspapers can provide a valuable check on each other in criticizing ethically questionable journalistic practices, but only when they ensure that they are not guilty those practices themselves.
As long as the Times feels it should look into conflicts of interest among newspaper staff, how doing something about the multiple instances of revolving-door hiring at the Times and elsewhere--a trend that the Times itself has documented. Just a thought.