Why a black first lady is a marketing gold mine.

When Michelle Obama sported a fetching J. Crew outfit on Jay Leno's Tonight Show in late October, she referred to her matching yellow skirt, blouse, and sweater as a "J. Crew ensemble." The three pieces sold out immediately. Traffic to the site was 464 percent higher than the day before; the company ingeniously added Michelle and Obama search terms within its site that would lead to a page featuring her outfit, with the headline, "all politics aside ... this outfit gets our vote." The retailer may be struggling these days, its stock trading at a 52-week low, but at least for the moment it has the best free advertising in the land.

This will hardly be the last time that Michelle Obama will have American women reaching for their credit cards. Her rise to mainstream sartorial prominence, like her husband's election, signifies a crumbling barrier: America is learning not just how race is lived but how it shops.

Ever since Andre Leon Talley coined the Obamas' "black Camelot moment" in Vogue's April issue, comparing Michelle O to Jackie O has been something of an obsession among style tastemakers. There is even a slyly titled Web site, Mrs. O, devoted to the subject. But Jackie Kennedy had no penchant for fashion for the masses, unlike our new first lady, who appeared on The View in June in a $148 cotton Donna Ricco number. The dress flew off the racks.

That day, Whoopi Goldberg commented on how unusual it was to see a smart, powerful, and, yes, beautiful woman on television who was "not very fair-skinned," but "dark black." Black women in popular culture, and especially in fashion marketing, are nothing new. Catalogs tend to feature at least one black woman in each season's lineup, but these faces look little like Michelle Obama's. There's nothing Beyoncé, not even Tyra, about her—no one would consider casting Michelle to play, say, Cleopatra. While some people might (absurdly) question whether Barack is black, you'll never hear that conversation about his wife.

Michelle’s race may break some barriers that, while not as momentous as those broken by her husband, are nonetheless historic. Vogue always features a new First Lady in their glossy pages. But not one of them—not even Jackie O—ever made the cover upon moving into the White House (Hillary Clinton’s 1998 cover was more of a launch of her own political career than a nod to her husband’s victory). And since the magazine’s 1892 launch, only four times have African-American women been featured on its cover: Beverly Johnson*, Oprah, Jennifer Hudson, and Halle Berry. Now, although the venerable magazine is still noncommittal on the record, word is that Michelle Obama will grace the cover soon. When More ran her on the cover—in a very Jackie pink sheath—the issue became one of the year's top sellers. Editor Lesley Jane Seymour said it was the most talked about cover in a couple of years.

Marketing and branding consultants are already salivating over, how, as Seymour put it, Obama "creates a lot of noise." The ones I spoke with say her draw isn't the aspirational power of nouveau Camelot, but rather her “realness.” In other words, her marketing power won’t be measured by whether her victory dress sends the well-heeled to designer Narciso Rodriguez’s spring trunk show. Instead, especially in these times, her force is a mainstream gale. You know it when the administrative assistant in your office shows up in one of the H&M outfits Obama sported on the campaign trail.