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.

Again, a consumer example may be the best way to explain. I love listening to music. And years ago, when I was peripherally involved in producing a couple of albums, I first encountered a “high-end” audio system. It was a revelation, and over the years it has proved an expensive one. I became an audiophile. We are a group easily (and regularly) lampooned—a few examples of the most expensive equipment (speakers that cost $150,000, CD players that cost $65,000, etc.) and a dismissive phrase or two usually suffice. Yet at much lower price points there is great sound to be heard. There is a small journalistic niche for this hobby (in the U.S., the flagship publications are Stereophile and The Absolute Sound). Both publications do a good job, in their different ways.

Their writers are, in my view, real experts. And given the relative paucity of information available, they have a lot of influence on the market (more, I think, than any car magazine has). But a central problem here is simply the variety of the equipment. If you are shopping for a pair of stereo speakers and want to spend under $2,000, it is pretty much impossible to find a reviewer who has had the chance to listen to even a large sample of what’s available, let alone all of it. And to complicate matters further, one of the problems with the audiophile press is the suspicion, often voiced in letters from readers (and denied energetically by the publications), that they are biased in favor of their own advertisers. Similar suspicions trouble readers of car magazines and other enthusiast publications, and these doubts are part of the distrust of the media that we are all too familiar with.

Today, I have an alternative: I can consult any of dozens of online audio forums to learn the views of other hobbyists about, say, two different pairs of speakers. You can usually find someone with an opinion on the equipment you are interested in—but you have no idea how reliable that person’s knowledge, or judgment, is. The experience of reading these online posts is a lot like one of the staples of entry-level magazine work—reading unsolicited manuscripts. With little or no background information on the writer, one must judge on the basis of the internal evidence—logic, coherence, and so forth. Illiteracy, incoherence, and a variety of pathologies are routinely on display. But among the dross there is gold, and an online forum can be a great place to get information, even if the sample size in high-end audio does not rise to the level of “wisdom of the crowd.”

If we leave the rarefied world of high-end audio for that of mass-market consumer products, there is still too much variety to comprehend. Anyone who has tried to buy a digital camera recently has faced the problem—new models are coming out all the time. And again, as in the case of car shopping, this aggregation of consumer opinion can be helpful, particularly for those with niche interests.

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.