The “citizen” reviewers online, though, are all over the place. You have to be patient, and perhaps obsessive, to read through their reviews. Reading them gives one a new appreciation for journalists (and in particular for copy editors). And there are usually a lot of them. For the Honda Odyssey, for example, there were fifty-five reviews when I last checked the Edmunds site. These veered from the doting (“Boy am i happy with this van, It’s everything i had heard and read and more”) to the niche (“add a second 12V receptacle in front console”) to the outraged (“The sliding door fell of it’s track onto my 7-year-old’s foot.”). But when you start reading, you can cull some interesting information.

And sometimes the user-generated reviews are the best place for up-to-date and specialized information. Edmunds, for example, had not yet rated as of late July the new Honda Pilot, but sixteen consumers had already weighed in. And some of the information is really useful for me. One reviewer, asked to suggest improvements that could be made to the car, wrote: “One of the biggest improvements would be to remove/redesign the glove box. [This] . . . would allow passengers over 6’4’’ to fit comfortably.” This may not matter to you, but I am over six-feet, six-inches tall, and my wife likes to drive, so a lack of leg space in the shotgun seat is a deal-breaker for me. This is an example of how the new resources of the Web and customer reviewing provide information that can shape the part of the distribution curve that Wired magazine editor-in-chief Chris Anderson dubbed “the long tail.” In his book of that name (with the informative subtitle: Why the Future of Business Is Selling Less of More), he highlighted the ability of companies in an Internet age to make money selling smaller quantities of products (books and recordings being prime examples) to niche audiences.

This new situation puts traditional retailers at a disadvantage. A brick-and-mortar store, for example, cannot afford to stock a deep inventory of DVDs, so it has to try to make its profits on the big hits. Yet Wal-Mart and big-box stores like Costco use those same big hits as loss leaders, to get customers into their stores. Thus, specialist retailers have been losing these sales of popular items on one side due to price pressure, and cannot compete with the limitless inventory of Amazon and the like on the other. Journalists have written this story about independent record stores and book stores many times, and now journalism is facing similar pressures.

What is true of brick-and-mortar stores is also true of mass-market journalism. The hits—sports news, stock-market information, weather forecasts—can be found elsewhere. Toward the other end of the curve, meanwhile, niche information is more broadly available on the Web than in the newspaper. A general readership is not likely to care much about the special requirements of car buyers who are two meters tall, or baseball fans devoted mostly to Japanese players in the major leagues, so the mainstream media are not likely to include such material routinely in reviews or articles. And if I want opinions about my team (the Yankees), there are dozens of blogs to choose from, including those of beat reporters from New York-area papers, as well as blogs devoted to individual players (including Hideki Matsui).

The narrower the interest, the more likely I am to find it satisfied outside traditional media. The broader the interest, the more likely I am to find it offered by someone with a stake in the subject that is non-journalistic, such as MLB.com, for baseball news. By training and belief, I am much more likely to want to get my information from a journalistic source. But there is no reason to believe that my preference is very widely distributed among the population. In short, the farther out the long tail I go, the more likely I am to be ill served by the mainstream media, and the more I am apt to rely on the opinions of fellow consumers.

Evan Cornog , former associate dean for academic affairs at Columbia's Graduate School of Journalism and the former publisher of CJR, is dean of the School of Communication at Hofstra University.