While it remains to be seen whether user-driven news sites will make traditional news editors obsolete, those who contribute to social news sites clearly make different editorial choices than their professional counterparts.

A report released on Wednesday by the Project for Excellence in Journalism (PEJ) compared what the mainstream media considered to newsworthy for one week -- the week of June 24 to June 29, 2007 -- with the news selected by user-driven news sites during that same period.

While the mainstream media focused on Iraq and the debate over U.S. immigration, the three leading community news sites -- Del.icio.us, Digg, and Reddit -- featured stories about Apple's iPhone and Nintendo's net worth surpassing Sony's.

"In short, the user-news agenda, at least in this one-week snapshot, was more diverse, yet also more fragmented and transitory than that of the mainstream news media," the PEJ said. "This does not mean necessarily that users disapprove or reject the mainstream news agenda. These user sites may be supplemental for audiences. They may gravitate to them in addition to, rather than instead of, traditional venues. But the agenda they set is nonetheless quite different."

The PEJ appears to be making an effort not to characterize its findings, as per journalistic tradition. It refers to the sources user news sites draw on -- seven out of 10 stories on user news sites come from blogs or Web sites like YouTube or WedMD -- as "strikingly different" from those of the mainstream media. Not good, not bad, just ... different.

Author and tech blogger Nicholas Carr observes no such niceties in writing about the PEJ's findings.

"When you replace professional editors with a crowd or a social network, you actually end up accelerating the dumbing-down of news," he said. "News becomes a stream of junk-food-like morsels. The people formerly known as the audience may turn out to be the people formerly known as informed."

What the PEJ and Carr neglect to consider is the extent to which professional editors, now armed with data detailing which stories get hits and which don't, are contributing to the dumbing-down of news (or, arguably, its improvement) by choosing to cover topics that get lots of readers (and thus better ad revenue) rather than the topics that are less popular but more "newsworthy."