One morning in early May, the online boutique Of a Kind released 60 gray canvas-and-leather bags, created by designer Anna Lynett Moss under the name Chiyome. At $150 each, they were flying off the virtual shelves.

Erica Cerulo, AB’05, one of the company’s cofounders, tweeted the depleting inventory. At 10:02 a.m.: “our 2nd @chiyome_ny bag (it’s a backpack! it’s a tote!) is going FAST. don’t say we didn’t warn you!” At 10:35 a.m.: “can count the number left on one hand ...” At 11:22 a.m.: “our @chiyome_ny bag sold out … in TWO HOURS.”

Launched in November 2010 as the first retail site on the Tumblr platform, Of a Kind is a combination online store and web magazine. Cerulo and cofounder Claire Mazur, AB’06, work with small, emerging fashion designers. Choosing men’s and women’s apparel, jewelry, and accessory designers whose work they love—“that’s pretty much the sole characteristic,” Mazur says—they collaborate with them to design exclusive, limited-edition pieces to sell on the site. Of a Kind has grown to include a network of more than 160 designers from around the United States.

Because Of a Kind only sells a small amount of each item, says Cerulo, there’s an urgency to purchase—the message is clear from the regular e-newsletter that lets people know how many new pieces are available and a “last call” on the website when the number of a certain piece is running low.

Cerulo and Mazur also publish stories about the personal and professional lives of each designer that they feature. A duo of designers, for example, shares their seven-step macramé guide; another offers her recipe for kale and tomato pasta. “Our approach with telling the story has always been to humanize the designers,” Cerulo says, “to make them feel like people that you want to be friends with.”

Plus, as Cerulo saw in her former job as a magazine editor at Details and Lucky, writing about products sells products. At Of a Kind, Cerulo oversees about 30 freelancers who write the stories, while Mazur handles product development, pricing, and photo shoots.

With about 100,000 unique page views a month and 40,000 newsletter subscribers, Mazur and Cerulo have become known as tastemakers. They received the award for Best Fashion Startup at the 4th Annual Fashion 2.0 Awards in March, and the industry blog Fashionista named them two of the 50 most influential people in fashion. “I think most fashion start-ups are selling an idea,” says Lauren Sherman, editor-at-large at Fashionista. “And they all need to be selling a product, which can mean a physical product, like Of a Kind’s editions, or a content-based product, like Of a Kind’s designer stories. They’ve got proof of concept. People actually buy the stuff they sell and read the stories they tell.”

The idea for Of a Kind was inspired by the company 20x200, founded in 2007 as an online gallery selling limited-edition paintings and prints. “It meant that artists could now sell their work and get their name out there without hooking up with a gallery, and consumers could buy art without having to go to a gallery and without having to spend a ton of money,” says Mazur, who wrote her arts administration master’s thesis at Columbia University on 20x200. “Barriers on both the consumer and producer side were suddenly gone because of this simple concept on the Internet.”

The women devised Of a Kind in early 2010, over 25 e-mails in 12 hours. They quit their full-time jobs in August of that year to start the company with $100,000 in seed capital from friends and family.

To launch the site, they worked with Mandy Coon, who designed one of the first items they offered: a tiny bag shaped like a bunny and named after Cerulo’s pet rabbit, Ernie—one of the bags now lives in a clear plastic trophy case in Mazur and Cerulo’s office. “I still can’t believe [Coon] took a chance on us,” Mazur says, “We were so green—and she was in Vogue. … She really took a risk.”

It paid off. Of a Kind soon attracted customers interested in merchandise over a wide price range ($20 to $435). Their core demographic is 20- to 30-year-olds who often shop at J.Crew and Etsy and aren’t “as price sensitive as they are value sensitive,” Cerulo says. They’re willing to pay for the Of a Kind message, aesthetic, and quality, and they know that the pieces will last for more than one season. Sherman of Fashionista—also an Of a Kind customer—says: “The look is super sophisticated and indie cool at once, but it’s not trendy. You never think, ‘Ew, I think that’s going to look terrible next year.’”

Now that it’s got the limited edition side down, the company is about to add a new element. In late summer or early fall, Mazur and Cerulo hope to launch Of a Kind Collections, selling the full lines of a lot of the designers whom they’ve featured. They realized that shoppers wanted “to become long-term, loyal customers of these designers,” Mazur says, “so they were going off and buying the rest of the collections from somebody else.” For Collections, Of a Kind will take a commission of each sale, and Mazur and Cerulo will handle the customer service. It will be set up like a well-curated online boutique, but with the editorial features Of a Kind customers have come to expect. Cerulo and Mazur hope that when someone compliments a customer on say, her Szeki Chan pocket shift dress, she’ll share the story about how the 7115 designer used to be a pop singer in Hong Kong.

 “We think of what we do as a new take on retail,” Mazur says. “Retail is like, ‘Here, put it on a shelf and hope consumers like it. Maybe if you’re lucky, we’ll put something with your name on it right there.’ But that’s not doing a lot for the designer. And I think what we try to do is a more thoughtful form of retail.”