Bloggers, "crowdsourcing" and computer-generated articles are making contributions to the news media, but they cannot replace professional journalists in digging up important news.
That is the message of a major study released this week by Columbia University's Tow Center for Digital Journalism, titled "Post-Industrial Journalism."
The authors of the report said technology has led to an explosion in the amount of information available, with economic shifts which are affecting journalism in both negative and positive ways.
But in certain kinds of reporting, professional journalists cannot be replaced by machines or crowdsourcing, the study said.
It is not journalism's best moment if much key work were taken over by amateurs, or done by machine, the study said.
"What is of great moment is reporting on important and true stories that can change society. The reporting on the Catholic Church's persistent harbouring of child rapists, Enron's fraudulent accounting and the scandal over the Justice Department's Operation Fast and Furious are all such stories."
The role of the journalist "as truth-teller, sense-maker, explainer - cannot be reduced to a replaceable input... we need a cadre of full-time workers who report the things someone somewhere doesn't want reported," the authors said.
But because of the changes to the media, the report said the advertising-supported model of newspaper and broadcast journalism may never be the same, and this means news "has to become cheaper to produce".
"There is no way to preserve or restore the shape of journalism as it has been practiced for the past 50 years," said authors C.W. Anderson, Emily Bell and Clay Shirky.
They said the changes have lead to "a reduction in the quality of news in the United States," and added: "We are convinced that journalism in this country will get worse before it gets better, and, in some places (principally midsize and small cities with no daily paper) it will get markedly worse."
The report argued that social media, blogs and "crowdsourcing" can have a positive influence by generating content not available in the past.
The authors note that the first reports on the raid killing Osama bin Laden came from a Pakistan IT consultant who tweeted what he witnessed, and that social media provided a more complete view of the Japan 2011 earthquake and tsunami than any individual journalist could provide.
They also conclude that tech startups like Palantir, Kaggle and Narrative Science which produce news stories from raw data through algorithms are also useful, and can free up professional journalists for other tasks.
The study said news reporting has always been "subsidised" in some manner, usually by advertising, and that a shift to online news with lower revenues has led to a search for a new model.
"The American public has never paid full freight for the news gathering done in our name. It has always been underwritten by sources other than the readers, listeners or viewers," the report said.
To make the economics work, the authors suggest flexibility: "Income can come from advertisers, sponsors, users, donors, patrons or philanthropies; cost reductions can come from partnerships, outsourcing, crowdsourcing or automation. There is no one answer."
One development in the media is the emergence of sites like the Huffington Post which maintain content from rival news organisations is "fair use," which can be taken in some form without payment.
"HuffPo management realised that fair use, as applied on the web, meant that, in essence, everything is a wire service and that excerpting and commenting on unique content from The Washington Post or The New York Times was actually more valuable to readers than contracting with the AP or Thomson Reuters," the study said.
"The Huffington Post has often been criticised for this stance, but this is shooting the messenger - what it did was to understand how existing law and new technology intersected."
The study concludes that because readers use a variety of sources, news organisations must therefore find a niche.
"There is a place for careful, detailed analysis... There is a place for impressionistic, long-form looks at the world far away from the daily confusion of breaking news. And so on," it said.
"Not many organisations, however can pursue more than a few of these modes effectively, and none that can do all of them for all subjects its audience cares about."