These tastemakers, Gladwell concluded, are the spark behind any successful trend. “What we are really saying,” he writes, “is that in a given process or system, some people matter more than others.” In modern marketing, this idea — that a tiny cadre of connected people triggers trends — is enormously seductive. It is the very premise of viral and word-of-mouth campaigns: Reach those rare, all-powerful folks, and you’ll reach everyone else through them, basically for free. Loosely, this is referred to as the Influentials theory, and while it has been a marketing touchstone for 50 years, it has recently reentered the mainstream imagination via thousands of marketing studies and a host of best-selling books. In addition to The Tipping Point, there was The Influentials, by marketing gurus Ed Keller and Jon Berry, as well as the gospel according to PR firms such as Burson-Marsteller, which claims “E-Fluentials” can “make or break a brand.” According to MarketingVOX, an online marketing news journal, more than $1 billion is spent a year on word-of-mouth campaigns targeting Influentials, an amount growing at 36% a year, faster than any other part of marketing and advertising. That’s on top of billions more in PR and ads leveled at the cognoscenti.

Yet, if you believe Watts, all that money and effort is being wasted. Because according to him, Influentials have no such effect. Indeed, they have no special role in trends at all.

In the past few years, Watts — a network-theory scientist who recently took a sabbatical from Columbia University and is now working for Yahoo — has performed a series of controversial, barn-burning experiments challenging the whole Influentials thesis. He has analyzed email patterns and found that highly connected people are not, in fact, crucial social hubs. He has written computer models of rumor spreading and found that your average slob is just as likely as a well-connected person to start a huge new trend. And last year, Watts demonstrated that even the breakout success of a hot new pop band might be nearly random. Any attempt to engineer success through Influentials, he argues, is almost certainly doomed to failure.

“It just doesn’t work,” Watts says, when I meet him at his gray cubicle at Yahoo Research in midtown Manhattan, which is unadorned except for a whiteboard crammed with equations. “A rare bunch of cool people just don’t have that power. And when you test the way marketers say the world works, it falls apart. There’s no there there.”

And this is not, he argues, mere academic whimsy. He has developed a new technique for propagating ads virally, which can double or even quadruple the reach of an ordinary online campaign by harnessing the pass-around power of everyday people — and ignoring Influentials altogether.

Not everyone appreciates the mind bomb Watts has tossed into their midst. He says one music executive pronounced his work “bullshit” on the spot. But a growing group of marketers believes Watts is radically altering the way companies attempt to produce trends. “He is changing the way people think about the way we communicate,” raves Robert Barocci, president of the Advertising Research Foundation. “He’s one of the best thinkers in the industry today.” But is Watts right?

WATTS, IRONICALLY ENOUGH, is precisely the type of person you’d peg as an Influential: tall, gruff, and handsome; a jut-jawed Navy man who left the service to study engineering. A former rock-climbing addict, he solved his first big intellectual challenge after hanging from a cliff at Joshua Tree. He has written about his work in Harvard Business Review and The New York Times, as well as in his new book Six Degrees. His Australian accent is disarming, even when he’s assuring you that everything you believe is probably crap.

Watts’s journey into trend research began, improbably, with the snowy tree cricket. As a grad student in the mid-1990s, he was exploring the mystery of how crickets synchronize their chirping. Clearly, information about when to chirp spreads like a contagion through the cricket network; Watts began to wonder how information flowed through human networks.

So he began programming the first computer models of how influence spreads. Like a kid experimenting with The Sims, Watts created a virtual community of individuals, then “infected” one with a “virus” — a virtual disease, or contagious idea — to see how far it would spread. He fiddled with his models, varying the degree and frequency of “exposure” needed to pass along the virus. He noticed that the success of an epidemic varied dramatically with seemingly tiny changes in his virtual society.

Yet even as Watts was conducting his research, marketers were becoming increasingly convinced that trends were the product not of murky social forces, but of charismatic, connected social alphas. In truth, it was an old — even hoary — marketing concept, dating back to 1955, when the pioneering sociologists Elihu Katz and Paul Lazarsfeld wrote Personal Influence. They had argued that advertising affected society through a two-step process: Companies broadcast messages, which were then seized upon by “opinion leaders” who proselytized their peers. They weren’t talking about celebrities like Oprah or even Paris Hilton, but about the rare everyday people who catalyze trends. Reach those opinion leaders, Katz and Lazarsfeld argued, and you’d quickly convert the masses.

Gladwell reanimated this concept in The Tipping Point. To help illustrate the cultural sway of his hypernetworked protagonists, he tapped the renowned 1967 “Six Degrees of Separation” study by sociologist Stanley Milgram. In that experiment, Milgram had given letters to 160 people in Nebraska, with instructions to ferry them to a particular stockbroker in Boston by passing the letters along to a colleague socially closer to the target. It famously took roughly six links to deliver each letter. But in a finding that particularly excited Gladwell, it was the same three friends of the stockbroker who provided the final link for half the letters that arrived successfully. They were the Connectors, as Gladwell dubbed them, who govern the flow of social information. If you wanted to get to that stockbroker, you couldn’t approach just anyone. You had to go through those three friends. Possessed of huge Rolodexes, these folks are the gatekeepers, Gladwell wrote, “and the rest of us are linked to the world through those special few.”

Gladwell’s book laid out many other factors that can “tip” a trend. He described other influential types: Mavens, who love to collect information and help others make decisions, and suave Salesmen of ideas. In order to spread, an idea or product had to be “sticky,” and appear in a fertile social context. But as The Tipping Point climbed the charts, marketers fixated on Gladwell’s Law of the Few, his suggestion that rare, highly connected people shape the world. For anyone involved in pitchmanship, it was an electrifying notion, one that took a highly complex phenomenon — the spread of memes through society — and made it simple. Reach the gatekeepers, and you reach the world.

But Watts, for one, didn’t think the gatekeeper model was true. It certainly didn’t match what he’d found studying networks. So he decided to test it in the real world by remounting the Milgram experiment on a massive scale. In 2001, Watts used a Web site to recruit about 61,000 people, then asked them to ferry messages to 18 targets worldwide. Sure enough, he found that Milgram was right: The average length of the chain was roughly six links. But when he examined these pathways, he found that “hubs” — highly connected people — weren’t crucial. Sure, they existed. But only 5% of the email messages passed through one of these superconnectors. The rest of the messages moved through society in much more democratic paths, zipping from one weakly connected individual to another, until they arrived at the target.

Why did Milgram get it wrong? Watts thinks it’s simply because his sample was so small — only a few dozen letters reached their mark. The dominance of the three friends could have been a statistical accident. “And since Milgram’s finding sort of made sense, nobody even bothered to redo the experiment,” Watts shrugs. But when you perform the experiment with hundreds of successfully completed letters, a different picture emerges: Influentials don’t govern person-to-person communication. We all do.

THE MORE WATTS EXAMINED the theory of Influentials, the less sense it made to him. The problem, he explains over lunch in a Midtown restaurant, is that it’s incredibly vague. None of its proponents ever clearly explain how an Influential actually influences.

“It sort of sounds cool,” Watts says, tucking into his salad. “But it’s wonderfully persuasive only for as long as you don’t think about it.” For example, in The Influentials, Keller and Berry argue that trendsetters draw their social power from being active in their communities. Their peers naturally turn to them for advice. Need to buy a new car or navigate city hall? Everyone knows whom to trust. Gladwell, for his part, argues that trends spread like diseases; Influentials are the vectors who amplify and propagate the infection.

Fair enough, as a top-down view. But it’s murky, and for Watts, this is a critical flaw, because precision matters when you’re trying to explain highly social epidemics. Merely arguing that influence spreads like a disease isn’t enough, because, he says, diseases spread in very different ways. Some require multiple exposures; some don’t. Some reward “superspreaders,” and some don’t. (SARS broke out in Hong Kong not because the first victim was a superspreader but because a doctor mistakenly hooked him up to an aspirator — ventilating SARS-infected breath into the hospital air.)

As Watts argues, there are a lot of ways an Influential could convert the masses. Merely talking to a friend once could infect her with an idea. Or it might take several conversations. Or maybe Influentials are so persuasive they’re like trend vampires, and each victim they bite becomes hyperpersuasive too. Depending on how you define the specific mechanics of influence, you’d get totally different types of epidemics — or maybe none at all. But gurus of the Influentials theory never directly clarify these mechanics.

“All they’ll ever say,” Watts insists, is that a) there are people who are more influential than others, and b) they are disproportionately important in getting a trend going.

That may be oversimplifying it a bit, but last year, Watts decided to put the whole idea to the test by building another Sims-like computer simulation. He programmed a group of 10,000 people, all governed by a few simple interpersonal rules. Each was able to communicate with anyone nearby. With every contact, each had a small probability of “infecting” another. And each person also paid attention to what was happening around him: If lots of other people were adopting a trend, he would be more likely to join, and vice versa. The “people” in the virtual society had varying amounts of sociability — some were more connected than others. Watts designated the top 10% most-connected as Influentials; they could affect four times as many people as the average Joe. In essence, it was a virtual society run — in a very crude fashion — according to the rules laid out by thinkers like Gladwell and Keller.

Watts set the test in motion by randomly picking one person as a trendsetter, then sat back to see if the trend would spread. He did so thousands of times in a row.

The results were deeply counterintuitive. The experiment did produce several hundred societywide infections. But in the large majority of cases, the cascade began with an average Joe (although in cases where an Influential touched off the trend, it spread much further). To stack the deck in favor of Influentials, Watts changed the simulation, making them 10 times more connected. Now they could infect 40 times more people than the average citizen (and again, when they kicked off a cascade, it was substantially larger). But the rank-and-file citizen was still far more likely to start a contagion.

Why didn’t the Influentials wield more power? With 40 times the reach of a normal person, why couldn’t they kick-start a trend every time? Watts believes this is because a trend’s success depends not on the person who starts it, but on how susceptible the society is overall to the trend — not how persuasive the early adopter is, but whether everyone else is easily persuaded. And in fact, when Watts tweaked his model to increase everyone’s odds of being infected, the number of trends skyrocketed.

“If society is ready to embrace a trend, almost anyone can start one — and if it isn’t, then almost no one can,” Watts concludes. To succeed with a new product, it’s less a matter of finding the perfect hipster to infect and more a matter of gauging the public’s mood. Sure, there’ll always be a first mover in a trend. But since she generally stumbles into that role by chance, she is, in Watts’s terminology, an “accidental Influential.”

Perhaps the problem with viral marketing is that the disease metaphor is misleading. Watts thinks trends are more like forest fires: There are thousands a year, but only a few become roaring monsters. That’s because in those rare situations, the landscape was ripe: sparse rain, dry woods, badly equipped fire departments. If these conditions exist, any old match will do. “And nobody,” Watts says wryly, “will go around talking about the exceptional properties of the spark that started the fire.”

IT SHOULD COME AS NO SURPRISE that marketers have not all warmed to Watts’s work. In September, he presented his findings to a standing-room-only crowd at a meeting of the Advertising Research Foundation. Ed Keller — The Influentials coauthor himself — then gave a polite but heated rebuttal.

Watts’s computer models are “interesting,” Keller admitted, but too academic to reflect reality. In contrast, Keller argues, his firm has studied tens of thousands of Influentials by identifying people highly active in their communities, an elite 10% that engage in advice-giving conversation up to five times more frequently than the average American. “They’re fonts of word of mouth,” Keller insists. And ahead of the curve, too: In the 20 years he has been polling them, Keller has found they began using computers, mobile phones, and the Internet years before the mainstream. What’s more, his polls have found that more than two-thirds of people who get word-of-mouth product recommendations either buy something based on it, or plan to.

“The data are crystal clear,” Keller adds, when I call him up. “They give and receive advice more. If I had $100 to spend, and I could spend it focusing on the mass market or I could put some chips on a group that could get me somewhere between two and five times as much energy with word of mouth, well, they’re going to get my message out more quickly and more efficiently.” He points to a recent example: Before Nintendo launched its hugely successful Wii video-game console last year, it handed out thousands of demo units to “mom influencers” around the country, creating a “built-in base of evangelists.”

In any case, Keller concludes, “Duncan is making a straw-man argument. Because nobody, including myself, thinks that Influencers are the only group of consumers who matter.”

Keller makes good points (although it’s a bit hard to swallow his last assertion, given that the subtitle of his book flatly states that “one American in 10 tells the other 9 how to vote, where to eat, and what to buy”). And even Watts, for all his bombast, can be quite self-critical. “My models might be totally wrong,” he says cheerfully. “But at least I’m clear about what I’m saying. You can look at them, and tell me if you disagree. But none of these other thinkers are actually clear about what they’re saying. You can’t tell if they’re wrong.”

No researcher, he points out — including Keller — ever analyzes interactions between specific Influentials and the friends they’re supposedly influencing; no one observes influence in action. In essence, Keller appeals to common sense — our intuitive sense of how the world works. Watts thinks common sense is misleading.

Mind you, Watts does agree that some people are more instrumental than others. He simply doesn’t think it’s possible to will a trend into existence by recruiting highly social people. The network effects in society, he argues, are too complex — too weird and unpredictable — to work that way. If it were just a matter of tipping the crucial first adopters, why can’t most companies do it reliably?

As Watts points out, viral thinkers analyze trends after they’ve broken out. “They start with an existing trend, like Hush Puppies, and they go backward until they’ve identified the people who did it first, and then they go, ‘Okay, these are the Influentials!’” But who’s to say those aren’t just Watts’s accidental Influentials, random smokers who walked, unwittingly, into a dry forest? East Village hipsters were wearing lots of cool things in the fall of 1994. But, as Watts wondered, why did only Hush Puppies take off? Why didn’t their other clothing choices reach a tipping point too?

For his part, Gladwell is diplomatic. “Duncan Watts is exceedingly clever, and I’ve learned a great deal from his research,” he emailed me. “In the end, though, I suppose that I feel the same ways about his insights as I do about Steve Levitt’s disagreements with me over the causes of the decline in violent crime in the 1990s. I think that all books like The Tipping Point or articles by academics can ever do is uncover a little piece of the bigger picture, and one day — when we put all those pieces together — maybe we’ll have a shot at the truth.”

MARKETING, OF COURSE, has always relied heavily on instinct and intuition. Admen like to believe they’re creative geniuses, gifted at truffling out social trends (which is why, they hasten to point out, they’re irreplaceable). Joe Pilotta, research VP for a firm called Big Research (and one of Watts’s bigger fans), suspects marketers cling to their belief in Influentials partly because they’re lazy. They love the idea of needing to reach only a small group of people to “tip” a product, he says with a laugh. Plus, it strokes their egos: “Think about it. You’re saying, ‘I am in control — I am the biggest influencer, because I am going to influence the influencers!’ It’s an arrogance that only the corporate world could enjoy.”

But the Internet has cranked up the pressure to show a return on advertising dollars, spawning incipient panic at agencies worldwide. It is into this world that Watts has injected himself, with his unwelcome insistence that basic marketing wisdom be tested scientifically. “The whole reason why Duncan’s work upsets people,” Pilotta points out, “is that he demonstrates that the world is complex, that it’s not that easy.”

Actually, if you believe Watts, the world isn’t just complex — it’s practically anarchic. In 2006, he performed another experiment that chilled the blood of trendologists. Trends, it suggested, aren’t merely hard to predict and engineer — they occur essentially at random.

Watts wanted to find out whether the success of a hot trend was reproducible. For example, we know that Madonna became a breakout star in 1983. But if you rewound the world back to 1982, would Madonna break out again? To find out, Watts built a world populated with real live music fans picking real music, then hit rewind, over and over again. Working with two colleagues, Watts designed an online music-downloading service. They filled it with 48 songs by new, unknown, and unsigned bands. Then they recruited roughly 14,000 people to log in. Some were asked to rank the songs based on their own personal preference, without regard to what other people thought. They were picking songs purely on each song’s merit. But the other participants were put into eight groups that had “social influence”: Each could see how other members of the group were ranking the songs.

Watts predicted that word of mouth would take over. And sure enough, that’s what happened. In the merit group, the songs were ranked mostly equitably, with a small handful of songs drifting slightly lower or higher in popularity. But in the social worlds, as participants reacted to one another’s opinions, huge waves took shape. A small, elite bunch of songs became enormously popular, rising above the pack, while another cluster fell into relative obscurity.

But here’s the thing: In each of the eight social worlds, the top songs — and the bottom ones — were completely different. For example, the song “Lockdown,” by 52metro, was the No. 1 song in one world, yet finished 40 out of 48 in another. Nor did there seem to be any compelling correlation between merit and success. In fact, Watts explains, only about half of a song’s success seemed to be due to merit. “In general, the ‘best’ songs never do very badly, and the ‘worst’ songs never do extremely well, but almost any other result is possible,” he says. Why? Because the first band to snag a few thumbs-ups in the social world tended overwhelmingly to get many more. And who received those crucial first votes seemed to be mostly a matter of luck.

Word of mouth and social contagion made big hits bigger. But they also made success more unpredictable. (And it’s worth noting, no one in the social worlds had any more influence than anyone else.) So yes, Watts figures, if you rewound the world to 1982, Madonna would likely remain a total unknown — and someone else would have slipped into her steel-tipped corset. “You cannot predict in advance whether a band gets this huge cascade of popularity, because the social network is liable to throw up almost any result,” he marvels.

Predictably, the music industry received the analysis — “Experimental Study of Inequality and Unpredictability in an Artificial Cultural Market,” published in Science in 2006 — with a cocked eyebrow. When Watts presented his findings to executives at a major record label last spring, the younger among them were reasonably receptive. They’re accustomed to the unpredictability of hit-making online, so they can grasp the terrifying randomness of success.

But the older execs?

Watts laughs. “They were all like, ‘I think it’s bullshit. I’m still going to go with my gut,’” he recalls. “And I’m like, Okay, good luck to you. You’re going to need it.”

IF INFLUENTIALS CANNOT TIP A TREND into existence — and if success in a networked society is quite random — what’s a poor marketer to do? Is there any way to intentionally infect people with an idea or a product?

Watts believes there is. In the past three years, he has worked on a new form of advertising he calls Big Seed marketing (this is part of his work at Yahoo, where he is a principal research scientist). Watts developed the concept with a friend, Jonah Peretti, a veteran of the viral wars. While a student at MIT in 2001, Peretti had an email exchange with Nike that turned into an accidental pass-around hit, reaching 50 million people and catapulting him onto the Today show. A year or so later, a satirical Web site Peretti created in one weekend — blackpeopleloveus.com — amassed 30 million page views in a few weeks. Soon, companies were frantically trying to hire him to help their online ad campaigns “go viral.” Peretti partly disagrees with Watts about the randomness of trends; he thinks it’s possible to intentionally make a funny Web site into a pass-around hit online. But as Peretti discovered, real-world goods are harder. When he tried to pitch “some company’s shitty product,” he couldn’t force it to go viral.

In their hunt for a practical way to create maximum exposure for any given ad, Watts and Peretti developed a way to marry the benefits of old-school mass marketing with clever six-degrees effects. Their first test case came when the Brady Campaign, the gun-control group, asked for help with an online petition.

Watts and Peretti set up a regular mass-market ad buy, running banner ads on several prominent blogs and news sites. Like many ads these days, they added a button on the ad that allows people to forward the ad to a friend — a way of collecting eyeballs for free. Typically, people ignore this “share with your friends” pitch. But Watts and Peretti included technology called ForwardTrack, which displays the route the ad travels once you’ve forwarded it. This turned ad forwarding into a piece of social cartography. People would pass the ad specifically to those friends most likely to keep it moving. It became a Facebook-like contest to sign up the most friends.

The technique marries Watts’s two main epiphanies: Cascades require word-of-mouth effects, so you need to build a six-degrees effect into an ad campaign; but since you can never know which person is going to spark the fire, you should aim the ad at as broad a market as possible — and not waste money chasing “important” people. And it worked. The pass-around effect doubled the number of people who saw the Brady Campaign’s ad. They paid for 22,582 hits and received an additional 31,590 for free. Another campaign they ran for the Oxygen network quadrupled the audience size, adding 23,544 hits to the initial 7,064.

Neither was, technically, a viral hit. Neither passed the disease threshold, where the meme spreads exponentially and engulfs the mainstream. “But you can double your impact, which is still pretty good,” Watts says.

The ultimate irony of Watts’s research is that, if you really buy it, the most effective way to pitch your idea is … mass marketing. And that is precisely what the wizards of Madison Avenue, presiding over our zillion-channel microniche market, have rejected as obsolete. “But that’s the thing about magic,” says Watts. “If it sounds too good to be true, it probably is.”