Last month’s launch of the new feminine protection brand comprised several products designed for 14- to-24-year-olds and packaged to look more like cosmetic products than tampons.

The launch featured ads that made fun of the tampon-ad cliché of the menstrual period being a time to put on white gossamer gowns and dance on the beach. The company has begun a new phase of the campaign, a social-media push centering on it-girls the Kardashian sisters, stars of E!’s “Keeping Up with the Kardashians.”

The effort, developed with Web publisher Buzzmedia, includes a video series featuring Kris (the mother) and sisters Kim and Khloe. The five-video series is intended to express the idea that menstruation isn’t something that one should be ashamed of or avoid talking about. The videos are running on the Kardashian’s official Web sites and other Buzzmedia sites, including Celebuzz.com, Just Jared, and Whitney Port’s official Web site.

Doug Rohrer, chief revenue officer for Buzzmedia, tells Marketing Daily that Kotex is involved in several Web sites that together garner some 10 million unique visits from 12- to 24-year-old females.

“The indices are through the roof against this demo, and we as a company are tied very closely with a young female demo across all of our sites.” He says the Kardashians have a large following among young women, that Kim Kardashian’s site is the most popular celebrity site on the Web, and that she has a million or so followers on Twitter. “The Kardashians are strong in about every area in which you can measure digital,” he says.

One video has Mrs. Kardashian and the sisters introducing a series of videos of real people talking about what it was like to get their first period. Khloe Kardashian showed up for the launch event via Marina Maher Communications at New York’s Madison Square Park, where she broke through a faux brick wall meant to evince the campaign tag-line “Break the Cycle.”

Aida Flick, Kotex brand director, tells us that the effort was intended to get away from euphemisms about menstruation and speak honestly. “Girls today are watching reality TV — learning about things online. You can’t say ‘down there’ on TV, but you can see reality TV that shows just about everything….we have lost our connection to [girls and young women], so we wanted to poke fun at feminine care ads and start an open, honest conversation.”

The new Web site UbyKotex.com has a “Get Real” theme with features such as a section called “The Straight Scoop” where girls can post questions, which are then answered by a nurse, a peer and a mom. Flick says the site, which has been up for “a couple of weeks,” has gotten 700,000 views, 500,000 visitors interacting with the site, and 300,000 sample requests.

The effort includes a “Declaration of Real Talk” wherein Kotex has pledged a $1 donation to Girls For A Change for every woman who signs the Declaration online.

When a reality show about the Kardashian sisters of Calabasas debuted in fall 2007, most people had never heard of the family and what was known could scarcely be considered positive.

Their late father, a lawyer, helped O.J. Simpson win acquittal at his murder trial; middle daughter Kim palled around nightclubs with Paris Hilton; and a graphic sex tape featuring the brunet and a former boyfriend ended up in the hands of a porn distributor.

Two and a half years later, the Kardashians are an inescapable cultural and commercial force. Their series, “Keeping Up With the Kardashians,” which concludes its fourth season Sunday on E, has shattered viewership records for the cable network and spawned a spin-off show. Kim Kardashian.com is the world’s most popular official celebrity website, according to its operator. Checkout-aisle magazines and gossip blogs cover the smallest details of the sisters’ lives. And Madison Avenue calls on the family to sell mainstream America everything, from diet pills and orange juice to NASCAR and fast food.

Their popularity comes despite the fact that the sisters lack the talents that traditionally lead to superstardom and, some believe, partly because of it.

“There’s an aspirational quality to somebody who has become a celebrity for — and I don’t say this in an offensive way — but for not doing anything celebrity-worthy,” said Matt Delzell, an executive at Davie Brown Entertainment, a company that helps corporations choose celebrity endorsers. The young women to whom the Kardashians appeal, he said, “tend to think that’s pretty cool. That’s something I might be able to achieve.”

Television programming, especially on cable, is increasingly dependent on created rather than established celebrities. Turning nobodies — or virtual nobodies — into reality stars is cheaper than hiring actual somebodies. But the Kardashians have transcended that level. While personalities on Bravo’s “Real Housewives” franchises and MTV’s “Jersey Shore” and “The Hills” seem to exist to promote those shows, the Kardashians have turned their program into a promotional vehicle to expand their own empire.

Kris Jenner, the family matriarch and self-described “momager,” said she had little time for those who criticized her brood for being “famous for nothing.” She is too busy sorting through business opportunities, working on “SPINdustry” — a Kardashian documentary special debuting Sunday on E — and generally protecting what she only slightly self-consciously refers to as “our brand.”

“At a certain point, you have to put on your business hat and think of yourself that way,” she said recently.

“Keeping Up With the Kardashians” was conceived as a Hollywood version of “The Brady Bunch” — the harmless high jinks of a loving blended family against a backdrop of wealth and famous connections.

After divorcing Robert Kardashian, with whom she had four children — Kourtney, 30; Kim, 29; Khloe, 25; and Rob, 22 — Kris married former Olympic gold medalist Bruce Jenner, who had four children of his own. The couple had two more daughters, Kendall, 14, and Kylie, 12. From the beginning, Kim occupied the Marcia role — sexy and popular — but there were story lines for everyone.

Her sisters snagged their own show, “Kourtney and Khloe Take Miami,” last year and made headlines when Kourtney became pregnant by an on-again-off-again boyfriend and Khloe married Lakers’ sixth man Lamar Odom less than a month after they met. When the NBA champions and their families visited the White House last month, Khloe was photographed chatting with President Obama. Kim, meanwhile, agonized over whether to get back together with New Orleans Saints star Reggie Bush. (She did and showed up on the sidelines at the most-watched Super Bowl in history.)

Cameras recorded every tear and shriek and the audience spiked. “Keeping Up With the Kardashians” has averaged 3.7 million viewers this year, double last season’s total, and was especially successful in the young, female and free-spending demographic coveted by advertisers. According to Nielsen, Kardashian viewers tend to be single, college-educated women with no children, white-collar jobs and annual salaries of more than $60,000.

The show is the highest-rated series on cable among women ages 18 to 34, and occasionally beats even the network shows in its time slot for those viewers.

Why the Kardashians have succeeded where other programs purporting to show the real lives of beautiful people have not is the subject of much analysis in an industry eager to replicate them. Many credit the relationship between the sisters and their mother.

In spite of the sex tape, the quickie marriage and the out-of-wedlock child, the family still somehow manages to seem a model of sorts, said veteran celebrity journalist Bonnie Fuller. The sisters have their own homes, love interests and career prospects, but seem to enjoy nothing more than a good, long family talk at their mother’s kitchen table.

“It’s a modern-type of wholesome. We’re living in a very different world now. Sarah Palin’s daughter has a child out of wedlock,” said Fuller, the editor in chief of Hollywood Life, a celebrity and entertainment website. “Despite everything that has gone on with them, they come across as a very tight-knit family, and that appeals to women.”

Any conversation about the Kardashians’ popularity eventually touches on the sexual allure of Kim. The tape she made with rapper Ray J — she initially sued to stop it but later reached a settlement with distributor Vivid — is “definitely a best-seller,” a company spokeswoman said while declining to provide sales numbers. There was also a Playboy pictorial and her annual pin-up calendar. But she has managed to pull what marketers say is an unusual feat — appealing to men without pushing away women.

“She’s attractive to guys because she’s absolutely beautiful,” said Brad Haley, the executive vice president of marketing for CKE Restaurants, whose Carl’s Jr. burger chain hired Kim to promote its new chicken salad. But she also draws in women, he said, because “she’s not a waif-thin model. She’s got curves . . . and talks about how she’s got to diet and keep after her body.”

“[Our fan base] started off very male, but it’s transformed into a very heavily female base,” Kim Kardashian said Tuesday backstage at the New York runway debut of a new Kardashian fashion line from Bebe. “I think that’s because we’re not afraid to share our beauty secrets and our flaws. If I have cellulite, I’m not afraid to talk about it and try to find a product to make it look better.”

Beyond “Keeping Up” — which Kris Jenner calls “the mothership” — and its spinoff, the Kardashians stoke their tech savvy fans with an intense online presence. Kim’s website, where she blogs and posts answers to fan questions, gets more than 6.7 million page views a month, according to Quantcast. Khloe’s gets 3 million and Kourtney’s 2 million, according to site operators.

“They have embraced social media in a way that is profoundly different than other celebrities,” said Karina Kogan, chief marketing officer for Buzzmedia, a company that operates celebrity sites, including the Kardashians’. While Britney Spears, another Buzzmedia partner, relies on “a team of folks” to write the material on her site, the Kardashians most often handle it themselves, she said. The sisters routinely make news on Twitter or their blogs. When Kim wanted to refute reports that she had breast implants, she posted a photo of herself in a bikini at age 14.

How long the Kardashian franchise will endure is a subject that sparks debate. Kim’s appearance on “Dancing With the Stars,” which could have established her legitimacy as an entertainer with a broader national audience, fizzled when she was sent packing after two episodes.

“It remains to be seen how [the Kardashians] will do in the future. I don’t think the TV show has an incredibly long shelf life,” said Delzell, the branding executive.

But Kris Jenner is convinced otherwise. Asked to look 10 years in the future, she doesn’t hesitate.

“It’s ‘Keeping Up With the Kardashians,’ season 24. Kylie gets married,” she said.

Buzzmedia, a publisher of more than 30 pop-culture blogs and websites including JustJared, Stereogum and Okmagazine.com, and the official sites of Britney Spears, Ms. Port, Ms. Wilkinson and the Kardashian sisters, has spent the last few months creating branded promotions for its top talent. In July, Khloe and Kourtney Kardashian created designs for Ikea for its “Dash Across Ikea” dorm-room contest, which was featured heavily on the E! network stars’ personal blogs as well as other Buzzmedia sites. Another summer promotion paired Ms. Port with JCPenney for the contest, “Get Schooled in Style,” in which one fan could win a personal shopping spree with the star of MTV’s “The City.”

Now Buzzmedia is launching a new talent-services division to better accommodate these Web 2.0 endorsement deals. The unit is headed by Craig Bland, the company’s VP-celebrity programming and development.

Buzzmedia President Alan Citron, a former general manager at TMZ.com, described the new division as a “middle man between advertisers who we’ve become aware of through discussions of our properties and the needs they may have with celebrities,” with the celebrities’ own talent agents also playing key roles. “We’re not trying to get into their business. This is designed to be purely complementary to their business,” he said of the talent agencies.

In the case of JCPenney, Ms. Port and her reps at United Talent Agency participated in every step of the process, from having Ms. Port select her 15 favorite video entries for the styling contest to appearing in person at the launch of JCPenney’s first store in Manhattan. The contest resulted in a 5% click-through rate on JCPenney ads on WhitneyPort.com, editorial coverage in OK magazine, unsolicited user-generated videos posted by Ms. Port and contest-related tweets to her 300,000 Twitter followers.

Another summer promotion featured Ms. Wilkinson, former co-star of E!’s “The Girls Next Door” and current star of her own reality show, “Kendra,” facing off with the lead blogger at What Would Tyler Durden Do? in a blog battle of the sexes that helped promote Sony Pictures’ “The Ugly Truth.”

Doug Rohrer, a former sales chief for MTV Networks and Buzzmedia’s new chief revenue officer, argued that the relationships Buzzmedia is able to foster between celebrities and brands are among the most valuable in the marketplace. They’re also the hardest to execute, particularly as the value of word-of-mouth vs. paid social-messaging becomes more questioned than ever.

“[Paid tweets] are not something you can make people do, or even suggest, really,” he said. “You basically have to say, ‘Hey do you think this would be fun to do?’ For the most part we’re coming up with stuff that’s fun and creative for the celebrities. It’s not like they’re gonna retire on a tweet at the end of the day. They don’t need the money.”

Mr. Rohrer said Buzzmedia sites reach some of the most-engaged consumers of celebrity content, and collectively account for 12% of the traffic from 18- to 34-year-olds on the web.

“We come to the marketplace with a lot of brands that represent different things — authenticity, expertise and aspirational figures for the audience,” he said. “Our goal is always to connect the value of that audience with the advertisers in a meaningful way.”