A few months ago no one had heard of "podcasting" because it didn't exist. Last summer an MTV veejay turned technophile named Adam Curry wanted to do an Internet-based radio show, distributing it through his Weblog. (A Weblog, or blog, is a personal Web site where somebody self-publishes an electronic journal, often linking to other things on the Web that strike the author's fancy.) With the help of fellow bloggers, he created spe-cial software that allowed digital audio content to be distributed directly to an iPod digital music player. You could even "subscribe" to these audio feeds, automatically loading up your little gizmo with these "podcasts."

It's the kind of neat little innovation that in past times might have stayed under the radar for quite a while before others caught on.

But in these times, no cool idea goes unnoticed. Something as interesting as podcasting was bound to be embraced by the blogosphere, the interconnected tapestry of hundreds of thousands of Weblogs. But in specific slices of the sphere, opinion can be shaped by a much smaller number. By dint of reputation, novelty and charm, certain "alpha bloggers" have built large and influential audiences.

The bloggers who follow technology consist of a particularly evolved community, since some of them are pioneers of the technology of Weblogs themselves. The alphas, or "A-listers," as they call themselves, commonly cross-link to one another, with the effect of having one of their comments amplified and commented on. In the case of podcasting, they conducted a deep asynchronous conversation about the practice. Was this a new form of personal, do-it-yourself radio? Could it replace radio? Even though its workings were fairly esoteric--no one is close to making podcasting as simple a process as Apple has made music downloading--the accumulated buzz from the blogs became deafening.

The inevitable result was that podcasting suddenly became the hot topic in geekdom. In early October bloggers began keeping track of how many Google results you would get if you queried the word "podcasting." Day by day it rose... 5,950... 7,510... 13,000. By the end of the month it was more than 50,000, and by mid-November the number was 387,000. By that time the din of the blogosphere was too loud for traditional writers to ignore, and articles about podcasting appeared in the L.A. Times, The New York Times and BusinessWeek.

The lesson is that there's a new force--spearheaded by a relatively few people who work for no bosses and whose prose never sees an editor's pencil--that provides the water-cooler fodder for the larger high-tech community. Its power extends not only to high-tech cool-hunting but also to what's politically correct, geek-style. (Open source... gooood. Onerous copy protection... eeeevil.) And the significance of this phenomenon has some important implications for the way opinions will be formed in the decentralized world of Internet media.

What we have here is a new and unmediated link in the information food chain. Let's consider the tech bloggers who make up the A-list. (The political bloggers who got so much attention during the campaign have an A-list of their own.) No one hired them. No one appointed them. All you need to start your own Weblog is the software--which is low-cost, or free, and very easy to use--and something to say. Out of the inchoate chatter of the Web, the sharpest voices simply emerge. Certainly there are those--like Dave Winer, an early proponent who just completed a yearlong stint organizing a blog community at Harvard--whose reputation preceded them into the blogosphere. But more common are the people like Linux Journal editor Doc Searles, a long-respected tech observer whose well-read blog has made him a virtual brand, or Dan Gillmor, whose "We the Media" book is the blogging manifesto.

Other people, by a combination of writing skills, unyielding curiosity, canny instinct and lots of sweat equity, rise up from total obscurity to join the big dogs in the community. This happens when an A-lister notices a newbie's work and links to it. In those cases fame can come fast. Just ask Robert Scoble, an unknown when his items were first picked up by the alphas. "Within two weeks I was invited to Steve Wozniak's Super Bowl party," he says.

"There indeed is an A-list, as well as important niche influencers on smaller topics," says Dave Sifry, CEO of Technorati, a company that tracks the blogosphere. Technorati watches more than 4 million blogs. Most are isolated, and there are about 100,000 that have 20 or more "inbound" links (that means that a blogger has identified an item on someone else's Weblog and set up a one-click pathway for a reader to move directly to that item on the other author's site). But about 10,000 people have more than 100 inbounds.

Now we're getting into the realm of the alphas. Sifry keeps a running list of them, a geek hit parade of power brokers who zing arrows and shape opinions while quaffing lattes and using the Starbucks Wi-Fi. In the tech conferences you can often spot them in person, clustering toward the wall so they can keep their laptops plugged in. No matter where they are, they maintain a running conversation with their unseen audience, which can be as big as 20,000 visitors on a good day. And though no one pays for access to their homegrown publications, they can shape opinions, as the podcast example shows.

"The blogosphere is a tipping-point machine," says Searles, referring to Malcolm Gladwell's treatise on how ideas and trends can suddenly tilt from obscurity to ubiquity. A good idea gets amplified by the "echo chamber" of the blogosphere. It need not be the original thought of the blogger. In fact, as scientists from the HP Information Dynamics Lab wrote in a paper entitled "Implicit Structure and the Dynamics of Blogspace," ideas move on the blogosphere like viruses; the alpha bloggers spread concepts like Typhoid Marys. "They're movers, salesmen and connectors," says Searles.

They're also hard workers. In order to crack into the upper strata, you have to post frequently to stay on the fickle radar of this ADD-infested crowd. It certainly helps to be an excellent writer, like Halley Suitt, one of the few female alphas in the tech blogosphere. You have to link prodigiously to other blogs, increasing your profile and increasing the chances for inbound links. And you have to actually form strong opinions about what you're writing about--passion is required in a good blog. All of this takes time: Scoble spends two hours daily writing his Weblog and three more hours reading hundreds of other blogs in search of fresh ideas and nifty software innovations. "I want to be the first guy to spot the smart new guy or a cool new Windows app," he says. Even then you have no guarantee of blog fame. "What makes one person gain traction and another not?" asks Winer. "The same thing that makes one person a rock star and another a taxi driver."

And what do the alpha bloggers get in return? Certainly not riches. Though it's possible to pick up a few hundred dollars if you enlist in the program that carries Google's ad on your site, many A-listers don't bother. "If you're into blogs to make money, you're into it for the wrong reasons," says Searles. "Do you ask your back porch what its business plan is?"

Not that being an alpha blogger doesn't have some benefits. The exposure has led to better jobs, more lucrative consulting, speaking gigs and--if not groupies--a certain bit of glamour that comes from having people hang on your every word at the end-of-day reception at a tech conference. Traditional journalists, who follow the blogosphere closely for early warnings of the next trends, see these free agents more and more as peers. And public-relations reps are beginning to include the power bloggers in briefings and pitches.

Does this mean that the ultimate outsider community might wind up becoming a bit too entrenched in the establishment? Rest assured that before that happens, the unwashed blogging hoi polloi will shame the A-listers back into maverickville --or take their places. All it takes is a few important inbounds, a mention on the popular Slashdot geek site or, heaven forfend, a nod from traditional media. And someone you never heard of is suddenly a star on Technorati. "People come out of nowhere and get discovered," says Scoble. "Suddenly they have 4,000 readers a day." Who will be the one who discovers what comes next after podcasting?