huffpost.png A group of middle school students at Brooklyn’s Urban Assembly Academy of Arts and Letters got a special treat one March afternoon in 2011. Just five weeks after the announcement of the $315 million deal in which AOL acquired The Huffington Post, AOL’s chief executive, Tim Armstrong, and Arianna Huffington, HuffPost’s co-founder, came to the school to teach a class in journalism.

The lesson—or what one could see of it in the short, treacly video account that ran on The Huffington Post—may have told more about the future of the news business than what either Huffington or Armstrong intended. A few moments after the video begins, an official of the program that arranged the visit speaks to the camera: “We are delighted that Arianna Huffington and Tim Armstrong are going to be teaching a lesson on journalism!” What the video showed, though, wasn’t a lesson in how to cover a city council meeting, or how to write on deadline. Instead, the teachers in the classroom told her students, “We’re going to give you headlines that we pulled from newspapers all over the place, and you guys are going to place them and decide what type of news they are.”

This, then, was a lesson in aggregation—the technique that built Huffington’s site up to the point that AOL wanted to buy it.

In just six years, Huffington has built her site from an idea into a real competitor—at least in the size of its audience—with The New York Times. The Huffington Post has mastered and fine-tuned not just aggregation, but also social media, comments from readers, and most of all, a sense of what its public wants. In the process, Huffington has helped media companies, new and old, understand the appeal of aggregation: its ability to give prominence to otherwise unheard voices and to bring together and serve intensely engaged audiences, as well its minimal costs compared to what’s incurred in the traditionally laborious task of gathering original content.

HuffPost’s model has provoked sharp criticism from, among others, Bill Keller, executive editor of The New York Times, who, like Captain Renault in Casablanca, appears shocked that aggregation is going on. “Too often it amounts to taking words written by other people, packaging them on your own website and harvesting revenue that might otherwise be directed to the originators of the material,” Keller wrote. “In Somalia this would be called piracy. In the mediasphere, it is a respected business model.” He wrote this even as the Times’s own site has demonstrated the power of aggregation in many ways, notably in a blog called The Lede, which has deftly captured the tempo and texture of such ongoing stories as the protests in Iran and the upheaval in Egypt by blending Times reporting with wire reports and original material from outside sources.

In fact, almost all online news sites practice some form of aggregation, by linking to material that appears elsewhere, or acknowledging stories that were first reported in other outlets. An analysis of 199 leading news sites by the Pew Project for Excellence in Journalism found that most of them published some combination of original reporting, aggregation, and commentary and that the mix differed considerably depending on the management strategy, the site’s history, and—to be sure—its budget.

Pew categorized forty-seven of the sites it surveyed as aggregators/commentators and 152 as primarily producers of original content. In the aggregator/commentary group, four-fifths of the sites were online-only; of the original-content group, four-fifths were connected to traditional media. Traffic is highly concentrated at the top of the list, with the top ten sites accruing about 22 percent of total market share. Seven of the top ten sites are “originators.”

What is surprising is that consumers use these different kinds of sites quite similarly. Original-content sites do marginally better at keeping visitors for longer stretches and leading them to more web pages, but it is hard to imagine that this slightly higher engagement is enough to help cover the costs of original production and reporting.

Huffington often says that aggregation benefits original-content producers as much as it does the aggregators. The story of a recent blog post on New York magazine’s site makes for a good illustration.

At about the time that Huffington and Armstrong were visiting the school in Brooklyn, Gabriel Sherman, a contributing editor to New York, was nailing down a scoop. Under the headline “Going Rogue on Ailes Could Leave Palin on Thin Ice,” Sherman reported that Roger Ailes, the head of Fox News, had warned his paid commentator, former Alaska governor Sarah Palin, not to go forward with her video accusing the media of “blood libel” in the way they portrayed conservatives after the shooting of Arizona representative Gabrielle Giffords.

Bill Grueskin, Ava Seave, and Lucas Graves are the co-authors of "The Story so Far: What We Know About the Business of Digital Journalism." Grueskin is dean of academic affairs at the Columbia University Graduate School of Journalism. Seave is a principal of Quantum Media, a NYC-based consulting firm. Graves is a PhD candidate in communications at Columbia University. For further biographical details, click here.