Of the many and conflicting stories about how The Huffington Post came to be—how it boasts 68 sections, three international editions (with more to come), 1.2 billion monthly page views and 54 million comments in the past year alone, how it came to surpass the traffic of virtually all the nation’s established news organizations and amass content so voluminous that a visit to the website feels like a trip to a mall where the exits are impossible to locate—the earliest and arguably most telling begins with a lunch in March 2003 at which the idea of an online newspaper filled with celebrity bloggers and virally disseminated aggregated content did not come up.

The invitation for the lunch came from Kenneth Lerer. He was 51 and casting about for something new, having recently left his position as executive vice president for communications at AOL. Lerer was a private man who was nonetheless comfortable in the presence of powerful people with whom he had earned a reputation for honing images in disrepair, most famously for the disgraced and subsequently rehabilitated junk bond trader Michael Milken. Lerer had made a good deal of money and a good many friends after having first made a name for himself in the quixotic 1974 New York senate campaign of Ramsey Clark (for which he was hired by the chairman of this magazine, Victor Navasky, who later recruited him for CJR’s Board of Overseers, which has no say in content). Lerer was splitting his time between New York and skiing at his vacation home in Utah when he came across a new book by a young sociologist, Duncan Watts. The book was called Six Degrees. Lerer was so taken by it that he took Watts to lunch.

He brought the book with him and Watts would recall that the copy was dog-eared, the flatteringly telltale sign of a purposeful read. Lerer had a plan and he wanted Watts to help him. He had set himself an ambitious target. He wanted to take on the National Rifle Association.

He told Watts: “I know the answer to this is somewhere in these pages.”

Nine years and one Pulitzer Prize later, what is the phenomenon that lunch set in motion? How is it that The Huffington Post, at turns celebrated as the savior of its parent company and decried as a glitzy thief of journalism produced by others, has come to matter?

Before its purchase by AOL in February 2011, HuffPost was not a property that had produced much in the way of revenue; it had posted a profit only in the year before the sale—the amount has never been disclosed—on a modest $30 million in revenue. Aside from scoops from its estimable Washington bureau, it did little in the way of breaking stories, the industry’s traditional pathway to recognition.

Huffington Post, which had mastered search-engine optimization and was quick to understand and pounce on the rise of social media, had been at once widely followed but not nearly so widely cited. But that is likely to change now that it can boast of a Pulitzer Prize for national reporting—the rebuttal to every critic who dismissed HuffPost as an abasement to all that was journalistically sacred.

Arianna Huffington liked to boast that the site that bore her name had remained true to its origins. The homepage’s “splash” headline still reflected a left-of-center perspective; it had thousands of bloggers, famous and not, none of them paid; and while there was ever more original content, especially on the politics and business pages, the site was populated overwhelmingly with content that had originated elsewhere, much of it from the wires (in fairness, an approach long practiced by many of the nation’s newspapers). But Huffington Post had evolved into something more than the Web’s beast of traffic, blogging, and aggregation. These days, Arianna Huffington has a regular seat at the politics roundtable, which speaks not only to her own facility on TV but also to the prominence her organization enjoys.

Power can be felt, even if it defies measurement. By the winter of 2012, Huffington Post could lay claim to a widely shared perception of its growing influence—the word Huffington prefers to power, which, she says, sounds “too loaded.” For better or, in the eyes of its critics, worse, Huffington Post had assumed the position of a media institution of consequence.

Michael Shapiro is a contributing editor to CJR and teaches at Columbia's Graduate School of Journalism. His most recent book is Bottom of the Ninth: Branch Rickey, Casey Stengel, and the Daring Scheme to Save Baseball From Itself.