The AOL Way was, with apologies to Maimondes, “a guide for the perplexed.” The problem was that AOL was neither a legacy news organization, which produced content that people would, in fact, want to read and share, nor did it have the DNA of, say, a Huffington Post.

The Huffington Post, however, was said to be looking for a buyer.

When Armstrong met Arianna Huffington, Huffington would later say, they hit it off so famously that by the end of that first meeting, they were finishing each other’s sentences. Two months later, AOL announced the purchase, $295 million of it in cash. Notably absent from the agreement was a non-compete clause. Ken Lerer left and started his own venture capital firm, Lerer Ventures, which Eric Hippeau soon joined. Peretti left for BuzzFeed. Berry would leave several months later and take up residence across a spacious room from Lerer Ventures—one floor below the original Huffington Post newsroom. HuffPost resided in the sleek lower Broadway office of AOL. Of the three founders of the Huffington Post, only Arianna Huffington remained. In a sense, she was just getting started.

She had moved back to New York from Los Angeles in 2010, and had quickly established her presence in the newsroom, to the confusion and occasional chagrin of all those young people who had grown accustomed to a workplace with no discernible adults. HuffPost was by then making big-name hires—Howard Fineman came from Newsweek that September. Peter Goodman and Tim O’Brien were hired from the Times. The HuffPost Washington bureau, which had begun as a one-person operation and which had celebrated the first time President Obama called on Sam Stein at a press conference, had grown to 26 reporters who, in a city where power is defined by whether calls get returned, now fielded complaints from the offices of both Harry Reid and Mitch McConnell.

By 2012, Huffington Post had grown so big that its critics—and even some of its fans—were beginning to suggest that, if anything, it had gotten too big, bloated with so many stories in so many verticals that it was leaving itself vulnerable to such new and more nimble content dissemination ventures. Not incidentally, Jonah Peretti’s BuzzFeed claimed 25 million monthly unique visitors in January. HuffPost was also, arguably, encumbered by a parent company that, despite, a late 2011 uptick in advertising revenue—and the reward of a boost in its stock price—had still ended the year with a 3-percent drop in fourth-quarter revenue.

Yet one metric spoke louder than any other about just what it was that Tim Armstrong concluded he was getting when he bought HuffPost: comment. In February, Ryan Grim, the Washington bureau chief, reported on a Houston gathering at which several wealthy men gathered to pool $100 million to stop the president’s re-election. As good as the scoop was, the response was even more telling: 21,000 comments. It was not unusual for HuffPost stories to generate comment measured in five digits. If, as essayist Paul Ford wrote, the fundamental question animating the Web is “Why wasn’t I consulted?” then Huffington Post could be fairly credited with succeeding at making a great many people feel that, in fact, they were being consulted, and better still, that HuffPost was grateful for their thoughts.

A quarter million comments land in HuffPost’s assorted in-boxes every day. The initial sorting—weeding out spam and offensive “trolls”—is done technologically; in 2010, HuffPost bought Adaptive Semantics, which had created software for evaluating the “emotional” nature of content, the better to ferret out the most vituperative screeds. But once that screening is done, the work of deciding what to post is left, intentionally, to people who work at HuffPost, as well as to the site’s most frequent commenters. In 2010, HuffPost decided to reward its most engaged readers with three “badges” that signify the extent of that engagement: “networkers,” who draw fans and followers; “superusers,” who share often on Facebook and Twitter and who also comment frequently; and “moderators” who, in recognition of their keen eye and absorption of the site’s ethos, are trusted with deleting comments they judge inappropriate.

Taken together, the badgeholders serve as voluntary traffic wardens for what truly makes Huffington Post so valuable to a company like AOL: Not brand. Not content. But access to the HuffPost network. It is not just the visit and page-view numbers, because those metrics, envied as they are, inevitably include a vast number of fly-bys, one-time visitors, the long tail of the Bored At Work network. But comments suggest loyalty, and loyalty—or engagement, to use the buzzy ad-world term—means an audience that advertisers can, in the ephemeral world of the Web, come close to counting on.

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.