What commenters don’t do is provide a sustained or inventive analysis of Applebaum’s work. In fact, critics hardly seem to connect one column to the next. In spite of Applebaum’s hard-to-miss hints that she celebrates Christian holidays (“On Christmas morning, my husband found a CD of ‘The Greatest Speeches of All Time’ in his stocking”), conspiracy-minded commenters insist that she’s Jewish and that her Jewishness determines her politics. And even though she makes it plain that her worldview coalesced when she was reporting on Eastern Europe in the ’80s and ’90s, commenters almost never address the intellectual consequences of her analogies between the cold war and the war on terror.

Someone should be paying more attention, especially since online newspaper commenters as a whole seem to have (at least) the stamina, drive and spare time to become a cogent part of online journalism. But as it is, online commentary is a bête noire for journalists and readers alike. Most journalists hate to read it, because it’s stinging and distracting, and readers rarely plow through long comments sections unless they intend to post something themselves. But perhaps the comments have become so reader-unfriendly, in part, because of the conventions of the Web-comment form.

Online commentary, for one thing, is a circadian art, one in which style and tone seem largely determined by the time of day a comment is posted. At washingtonpost.com, Applebaum’s columns typically receive around 100 or 200 responses before the site closes off the commenting option. (At Slate, which is online-only, registered commenters weigh in on the same column, but in a more formal way.) Immediately after the column appears online — often late at night — come early amens. Then dissent sets in, and a scolding tone emerges (“You should know better”; “Surely you jest”). In the later hours, things get more plaintive and surreal, as lonelier, insomniac imagery takes over and commenters begin to turn on one another. (Around 2 a.m.: “What has happened to the soul of The Washington Post?” and “The blood is on your hands. I’ll help you look for a rag, but don’t wipe it on my pants.”)

By the time the East Coast workday starts, responders seem showered, caffeinated and ready for battle. Comments of 250 words or more show up, and sometimes they’re itemized. These itemized entries borrow their structure from the blogosphere’s signature “fact-check,” a form in which a skeptic affects exhausted patience as he paces through a published argument point by point to show how perniciously or laughably wrong it is. These fact-checks are rarely potent enough to compel corrections by The Post, and Applebaum never replies to them.

Commenters, in short, rarely really sock it to a columnist. They also too often go automatic, churning out 100-word synopses of one stock ideological position after another. But most disappointing of all, for readers, is that commenters don’t, as literary critics say, read an article against itself to show how, for example, an argument framed as incendiary is in fact banal, or one that’s meant to be feminist is retrogressive, or one that touts its originality is a knockoff.