Almost two years ago, Chris Anderson, who is the editor of Wired magazine, published an article describing the intriguing features of markets — such as that for books, CDs and DVDs — in which scarcity is giving way to abundance. Anderson argued that unlimited selection — the 3.7 million books on Amazon.com versus the 100,000 available at your local Borders, to take one example — has occasioned a shift in the culture away from big hits and toward smaller niches. Anyone who has ever purchased media online knows this intuitively; which Netflix user hasn’t burst into frenzied delight at the possibility of renting every Preston Sturges feature instead of just the latest thing Will Ferrell’s starring in? But Anderson was the first to put a picture and a name to the phenomenon of unlimited selection, and he was greeted as a prophet of the new.

To understand what captivated people, you’ve got to look at the picture Anderson coined, a simple graph that orders the popularity of each title in a catalog from high to low — say, the popularity of every book in print, or of every DVD for sale. The diagram looks roughly like a hockey stick turned on its side. The blade of the stick represents hits, the few titles that, in any given time period, huge numbers of us are buying. Anderson calls this part of the graph the “head”; it’s in the head that you’ll find Will Ferrell. The rest of the graph — the shaft of the hockey stick — is the object of Anderson’s obsession. He calls it the “tail.”

Anderson’s singular insight was that, in a digital world, the tail goes on and on and on. Your local Blockbuster can’t waste valuable shelf space on something as unpopular as Preston Sturges’ oeuvre; since the shop maxes out at about 3,000 DVDs, there isn’t much room to stock items way down in the tail. But storing a DVD in a mail-order warehouse is much cheaper than storing it in a Blockbuster store, and storing a digital movie on an Internet server is essentially free. That’s the magic of online distribution: Netflix can carry all the Preston Sturges DVDs, and iTunes can keep the obscurest of covers, and YouTube can put up every inane or insane video ever captured by man. And according to Anderson, online merchants like Netflix, iTunes and others do a substantial business selling niche items. It turns out that there’s always someone, somewhere interested in watching old episodes of “He-Man and the Masters of the Universe” or whatever else you think would never ring your bell. Unlimited selection is allowing us to indulge our deepest media desires, and it’s big business, too.

Anderson could have called his idea the “Incredibly Tall Hockey Stick,” but he’s a huge Malcolm Gladwell fan, and thus he understands that if you want to get business people to home in on your idea, nomenclature is crucial. So he called it “The Long Tail,” and, like the “The Tipping Point,” the appellation is now nearly inescapable. At certain insufferable Silicon Valley cocktail parties you’ll find folks luxuriating over the phrase, gabbing about how to angle in on the true prize in Anderson’s insight, which he helpfully outlines in his book’s subtitle: “Why the future of business is selling less of more.”

Anderson and his fans have been ruminating over the “long tail” for a while now, and on Anderson’s blog and elsewhere, they’ve said a lot — you don’t understand, a lot — about the concept. During that time, Anderson also enlisted students and professors at some of the country’s most prominent business schools to help him research the matter. But for all this work, “The Long Tail” feels surprisingly free of new insight; it doesn’t say a great deal more than what Anderson offered in his breakthrough Wired article.

Certainly the book clarifies, bolsters, improves. The Wired piece carried the light step of theory, while the book has ambitions to a towering proof, with some tacked-on corporate how-to bits. The problem is, it’s a business book. Though he spends some time, here and there, discussing you and me, Anderson is mainly addressing those cheery SiliValley types looking to cash in on tail. As far as I can make out from his introduction, what got Anderson most juiced up about the long tail in the first place were the many conversations he had with new-media CEOs about their businesses. I’ve never met the man, but I’d hazard he’s the sort of fellow who actually has fun talking to CEOs.

Not that there’s anything wrong with that. Yet “The Long Tail” is about much, much more than how tech execs should design their online stores. The Web, iPods, iTunes, TiVo, Netflix, Amazon.com, e-mail, RSS, satellite TV, digital photography, cable news, talk radio, books-on-demand, the 500-channel universe, the information superhighway, the long tail: All these things are a really about one thing, and the thing is cultural fragmentation. The story of the long tail is the story of a dominant mass media shattering around us, and of what happens to society when we’re all forced to sort through the shards — all the information and the misinformation — that come at us in a world saturated by media. It’s true that one consequence of all this might be that more people will begin subscribe to Netflix and start renting a lot more niche DVDs. But that can’t be the full story.

In his defense, Anderson makes his interests clear all along. He came to Wired from the Economist, and it’s obvious that following the cultural fault lines created by media fragmentation isn’t his bag. As Anderson describes it in his introduction, his main quest is to determine how “long tail” economics will force “content producers” to adapt. His final chapter, “Long Tail Rules: How to Create a Consumer Paradise,” is the culmination of that mission — a step-by-step guide for CEOs to grab on to the tail.

My own interests require full disclosure as well. I’m as big a fan of digital tech as you can find, but I’ve long wondered, and sometimes worried, about the flip side to the media ubiquity we now enjoy, the paradoxical way in which having access to everything forces you to choose what you’re consuming. Indeed, this idea got me so hopped up that I’m currently writing a book about it.

Unlimited choice and easy access shake the world in unpredictable ways, causing people to splinter along the lines of niches they enjoy, and sometimes to lose touch with the world beyond. Today it’s possible to stop reading newspapers and instead get all your news from the Fox News channel — indeed, this is something many millions have done. Surely there are people who’ve decided that the only source they’ll trust for news on the Middle East is a favorite Haifa-based Likudnik blogger. In 2004, we saw huge numbers of people choose to believe something for which there was scant objective evidence — that John Kerry didn’t earn the medals he was awarded in Vietnam. Why did they do so? Not because they’re scurrilous, but rather because bloggers and talk-radio hosts they listened to spent months repeating such claims, and selective exposure, confirmation bias and a host of other psychological phenomena took over from there. The tail may go on and on and on, but does that matter if you’re only living in a few niches of it?

To put it another way, I worry about the filters. Because the long tail has everything in it, the only way to find anything useful there is by using some kind of filter. Often these filters are software-based aggregators of social thought: The New York Times’ “Most E-Mailed Story” list, Amazon’s “Customers who bought this item also bought …” feature, Netflix’s recommendations page, and even the Google search engine all enlist your own and others’ preferences to shape the world they present to you. But preferences don’t necessarily — and perhaps don’t often — coincide with truth. That’s why when you search for pentagon 9/11 you get a whole lot about why you shouldn’t believe the official story about what happened on that day. Even though the facts of the matter say something else entirely.

I’m not saying that the digital world will surely corrupt and ruin us. Far from it; I wouldn’t trade a world in which you can find BoingBoing for one in which you couldn’t. And “The Long Tail” is generally a thrill. People who aren’t familiar with how technology is changing the media business will likely find it a crisp introduction to some truly odd economic concepts. But there’s a good deal more uncertainty in this new world than Anderson lets on, especially for those of us who aren’t CEOs. I’m not looking to create a consumer paradise, and, chances are, neither are you. Yet the long tail is smacking us in the head all the same.

The clue: It’s the size of 10 refrigerators, has access to the equivalent of 200 million pages of information and knows how to answer in the form of a question.

The correct response: “What is the computer IBM developed to become a ‘Jeopardy!’ whiz?”

Watson, which IBM claims as a profound advance in artificial intelligence, edged out game-show champions Ken Jennings and Brad Rutter on Thursday in its first public test, a short practice round ahead of a million-dollar tournament that will be televised next month.

The “great vampire squid” of finance, Goldman Sachs, has invested $450 million in the emerging great vampire squid of cyberspace, Facebook. As the New York Times’ DealBook reported, the deal is gives Goldman a leg up on the huge fees investment banks will get when the social-networking company eventually sells shares to the public. And as the Times and Wall Street Journal also report, Goldman will also haul in huge fees from those clients who want to invest themselves.

UPDATED

(Please see the note at the bottom of this piece.)

Yahoo says it will try to sell its Web bookmarking service, Delicious. This news, posted on the Delicious blog, comes a day after widespread reports — unchallenged until now by Yahoo — that the company was shuttering the service.

One result of the earlier reports was a frenzied search for a new social bookmarking service to replace what many people, including me, have used over the years to stockpile and organize links to online material we’ve found interesting. A second result was a further hit to Yahoo’s declining reputation.

I just downgraded my Netflix account, and will be sending the company $7 less each month than I’ve been sending for several years now. Why? Because Netflix is moving fast to live up to its name — to become an online video-streaming operation instead of the DVD-rental outfit it’s been — but in the process it’s raising prices while making its service worse, in key ways, for longtime customers.

Google Inc. is addressing one of the biggest complaints about its free e-mail service by giving people more control over how their inboxes are organized.

The new option announced Wednesday will allow Gmail users to choose whether they prefer their incoming messages stacked in chronological order, instead of having them threaded together as part of the same electronic conversation.

Gmail has been automatically grouping messages by topic or senders since Google rolled out the service six years ago.

But this so-called “conversation view” confused or frustrated many Gmail users who had grown accustomed to seeing all their newest messages at the top of the inbox followed by the older correspondence. After all, that’s how most other e-mail programs work.