The Internet is often billed as a radical equalizer. Anyone with a keyboard can, we are told, compete for the readership of the largest magazines and newspapers. Anyone with a camera and a clever idea can, through YouTube, reach more viewers than MTV does.

There is a new meritocracy in the race for atten­tion, and it seems to threaten the establishment. Dan Rather, who spent much of his career shaping the official versions of news events, was edged into early retirement after bloggers exposed the doc­uments underpinning a major story as forgeries. Encyclopedia Britannica had to issue a defensive press release after a study in Nature suggested that Wikipedia, a user-created and free online encyclo­pedia, covers science just about as well as Britannica does. On rottentomatoes.com, movies are rated by the collective judgment of the large and anonymous viewing public, and famous reviewers sometimes find themselves in the back seat: how prominently a review is featured depends on how many people commend the review, not on who wrote it.

In each of these cases and many more like them, institutions that have traditionally derived their power from one-to-many communication are under­mined by the new ease with which regular people, acting independently, can reach a large audience.

The traditionally dominant media are losing our attention. The total audience of the network TV news shows has dropped by half since 1980. Because of all the new competition, our attention is becoming a more important commodity than ever. Several astute observers, including Michael Goldhaber and Richard Lanham, have pointed out that the phrase “information economy” is a misno­mer—information is not naturally scarce. Rather, we are drowning in it. The thing that is scarce, and that becomes more valuable the greater the deluge of information, is our capacity to absorb and process information—or, our intrinsically finite supply of attention. Attention is the crucial ingredient that allows information-driven goods such as music, writing, and expert advice to find their value in the marketplace.

Celebrities—people who are, as Daniel Boorstin put it, “well known for their well-knownness”—are more celebrated than ever. Once they rise to national or global renown, whatever the reason, their fame becomes a kind of capital that can be converted into money or political influence.

Bono’s allegiance to the “Make Poverty History” campaign has influenced the public mood enough that Western governments are now pledging to shovel more money into aid programs that have been spectacular failures. The Dixie Chicks, Whoopi Goldberg, and a crowd of other entertainers raise funds and votes for Democrats, while Nashville turns out patriotic anthems that rustle up support for Republicans. Tom Cruise may have done more to spread skepticism about psychiatry than Thomas Szasz has. (Haven’t heard of Szasz? He wrote The Myth of Mental Illness, the most widely read intel­lectual critique of the mental health establish­ment.) Madonna’s efforts to adopt a Malawian child have brought Africa into America’s public conversation, surpass­ing, at least for a time, the attention that actress Angelina Jolie has attracted as a spe­cial United Nations ambassador to refu­gees in Darfur.

Attention is the crucial ingredient that allows information-driven goods such as music, writing, and expert advice to find their value in the marketplace.

The logic of the Internet was supposed to wash away celebri­ties in favor of what Yochai Benkler and others call “crowdsourcing,” where we all collaborate to replace the experts or the divas. How is it that the star power of many big celebrities is still growing, and at the same time a stampede of new ones arrives—bloggers or musicians with cult follow­ings, talking heads on new cable networks, and community leaders like Jim Wales of Wikipedia? If big celebrities aren’t losing mindshare, and lots of new ones are gaining it, then what gives? What are all these celebs distracting us from?

The answer lies in what all celebrities have in common: they create a community of watch­ers who, by paying attention to the same subject, come to share knowledge and experiences with one another. The Internet opens up a risk of “data smog,” with each of us lost in his own self-selected haze of idiosyncratic interests. Celebrities furnish a cure, supplanting more time-consuming social platforms like churches and civic clubs. One major reason people watch Oprah Winfrey or Katie Couric is the brute fact that so many others are watching. Andrew Shapiro and David Shaw have pointed to these shared expe­riences as “social glue” that holds us together.

New technologies give us a wide range of ways to amuse ourselves in solitude. Tivo, the Web, and most notably the iPod provide solo experiences that are at least as enticing as traditional socialization. They are, if anything, too good—they cater to our individual tastes so well that we need not devote as much time to communal pursuits.

Historically, people have usually shared geo­graphic proximity and cultural ties with their most immediate social contacts. But many technology-watchers have noticed this changing. It’s hard to chat about the weather with a Facebook “friend” who lives in a foreign city, and church attendance is on the decline. Core curricula in universities are out of fashion. Daily papers, which once gave everyone in town something to talk about, are rapidly losing market share to more specialized sources.

Celebrities have retained their “convening power” as a basis for shared conversation even as more tra­ditional sources have eroded. Daniel Boorstin wrote with eerie prescience in 1961 that modern celebrity-driven media “provide that ‘common discourse’ which some of my old-fashioned friends have hoped to find in the Great Books.”

It’s not that we Americans are letting our brains rot; to the contrary, we are happily ensconced in an ever-expanding range of specialized pursuits. By eliminating the barriers of distance and allowing people to announce their most obscure predilec­tions to the world, the Internet has allowed far-flung aficionados of Brazilian jazz, South African wines, or Japanese cartoons to find one another and sus­tain communities of interest that simply would not have coalesced, given the higher search costs, in the pre-Internet era. But with so many niche interests, the common core has eroded, leading to an increase in the importance of celebrity.

America is constantly becoming more diverse, and has been advised by the Supreme Court that diversity should be regarded as a cardinal virtue. But this outlook—which could be encapsulated as “the less we have in common, the better”—is costly. It obscures the inevitable importance of common ground in social interactions. Part of the reason celebrities are so important is that we have refused to make a national commitment to a canon of great books, the rigorous study of American history, or anything else that might provide a sturdier plat­form for civic discourse than last night’s intrigue on “Survivor” or “Real World.”

B-list celebrities, such as the athletes known to sports buffs, the actors on “Star Trek,” or the talking heads on cable news, do the same thing for smaller groups that Tom Cruise does for the nation. Policy wonks from opposite coasts and different schools of thought can bond through critiquing the interviews they saw on “Meet the Press” or “Face the Nation.” “Star Trek” buffs can bond over Shatner re-runs.

Celebrity watching is the perfect common pursuit in our mediated, isolated information landscape. It holds us together. The further we venture into the individualized world of high technology and niche interests, the more important celebrities—for bet­ter or worse—will become.