At almost five years old, the beauty-subscription company Birchbox is out of its toddler phase. It’s a recognized brand, experiencing fast growth.

Yet, Birchbox’s CMO Deena Bahri refuses to accept that its early days of organic growth may come to an end, even though she acknowledges that it’s a lot harder to achieve.  “One of our most critical challenges is staying buzzworthy,” she says. “It’s why we continue to reinvent and reimagine our story — so that people want to keep talking about us.”

(We’re delighted that Bahri will be speaking at GrowthBeat Summit in Boston on June 1 and 2 — where reinventing the brand story is part of the theme of the exclusive CMO-only gathering. A key theme of the event is how to infuse creative storytelling in conversations with customers at the various stages of their journey, while leveraging technology to do so. Request your invitation to the event here.)

The company started by targeting women, offering them a way way to get personalized monthly Birchboxes filled with shiny new samples — by signing up online. In time, it added grooming products for men, and last summer it opened its first retail location in New York City. Some 70 percent of its revenue comes from subscriptions, with 30 percent originating from direct sales both online and in the retail store.

Last year, its investors pumped another $60 million in Series B funding into the company to expand on the company’s success. In the same way Uber has become a standard comparison for the on-demand consumer model (entrepreneurs like to say “We’re the Uber for X”), Birchbox defines the monthly subscription service model (“We’re the Birchbox for Y”). The premise is brilliant: By getting customers to spend $10 a month to receive samples — rather than the old days of free sampling — customers are actually paying to be “acquired,” in the sense that Birchbox can them move them down the purchase funnel to buy full-size products.

Partnering with buzzworthy brands is one way Birchbox continues to do that. When the final episodes of Mad Men began airing in April, Birchbox partnered with AMC to create special Mad Men-themed boxes. Birchbox partnered with JetBlue to feature travel-themed products targeted at people flying on that airline.

It doesn’t hurt that their product category is one that customers feel passionate about, lending itself naturally to sharing with bff’s.

“[Beauty] is a very social experience,” says Bahri, “and that’s a key part of our growth.”

Birchbox attempts to communicate its story, starting with the very first delivery. The company stokes social chatter and sharing continually, by teasing the arrival of boxes through Instagram posts and then prompting social sharing with deliveries by asking customers to reivew products or “Tell us your favorite way to use this product” or “achieve a certain look.” When consumers tell the brand’s story themselves, the brand benefits from that story reinvention over and over.

Says Bahri, “Sometimes the scary thing about a monthly subscription is that every month we have a chance to delight people — and every month a chance to disappoint them.”

Big data tips the brand’s scorecard in favor of the delight bucket. Customers complete detailed profiles so Birchbox can meet individual needs, but the company analyzes the data to see if customers are, indeed, behaving as anticipated. “We’re a very quantitative marketing team — we measure everything we do,” Bahra explains. This includes targeting emails, messages, and offers based on both preferences and past behavior. Got curly hair? You’ll get messages and product selections that match you. If you’re someone who’s gifted products in the past, you’ll continue to see campaigns to bring out your inner giver.

Despite its phenomenal success, Bahri’s not afraid to experiment and take risks. “It’s critically important to test and learn all the time, so sometimes our ideas work, sometimes they don’t.”

Join us for GrowthSummit and be certain to hear Bahri share more about how she’s reinventing her company’s story, and the lessons she’s learning while doing so.