Prologue
Before a baby arrives in the world, the very first thing parents see is a tiny heartbeat and a blurry shape on an ultrasound screen. Only a few years ago, that incredibly special moment used to be burned onto a CD that got shoved into a drawer and forgotten. There was no easy way to share it with family, even when you wanted to. Mamitalk solved that problem by making ultrasound clips effortlessly shareable from mobile — and from there, it grew into a comprehensive platform for expectant and new mothers across Korea.
Today, Mamitalk has an 80% advertiser re-booking rate, hit full booking the same day it launched its video ad product, and is used by roughly 90% of pregnant women in Korea. It's no longer just a parenting app — it's becoming a serious advertising platform. How did the team move that fast? We sat down with Goh Seung-kwon, Head of Business at Mamitalk, to hear the story directly.
Mamitalk: a nationwide "mom" community that started with ultrasound clips
Mamitalk is now an essential app for Korean moms — what do the numbers look like?
Over the past three years, I haven't met a single mom who gave birth without using Mamitalk. It's the platform that's fully nailed the touchpoint with expectant mothers.
450K monthly active users, 1.5M moms in total. Mamitalk delivers the essentials of pregnancy and parenting alongside a growing child. The Mamitalk community in particular is what moms use most — racking up more posts and pageviews than the country's nationwide mom-café network, and serving as the main place expectant mothers talk to each other. With mom users — the actual decision-makers on what gets bought — making up the largest segment, the user base also has serious purchasing power.
How are you growing into a platform that spans the whole life cycle?
Mamitalk has partnerships with about 90% of OB/GYN clinics in Korea — enough penetration that you can reverse-engineer the country's birth rate from the data. On the product side, we ship features like "Class" (pregnancy and parenting expert content) and "Baby Magic" (an AI preview of what your baby might look like), all calibrated to the user's specific week of pregnancy. Both the product and the ad business are built on top of each user's life-cycle stage.
The biggest edge Mamitalk has as an ad platform is precise pregnancy-week and birth data. Early pregnancy is the right moment for fetal insurance and prenatal screening ads. As due dates approach, safe vehicles and baby goods are the right fit. Post-birth, it shifts to diapers, formula, and toddler food — life-cycle-matched products, served at exactly the right time.
Inside Mamitalk's ad business
Tell us about the Ad Business team — what does it actually do?
Mamitalk has grown beyond a service for expectant moms into a platform representing women and families more broadly. Advertisers across maternity, parenting, beauty, automotive, vaccines, F&B — they all run with us. Our focus is making sure those advertisers run without friction, at high efficiency.
The Ad Business team is built around two roles: sales people who consult with advertisers, and operators who run data-driven experiments and squeeze out efficiency. That split lets the sales side go deep on strategic consulting, while operations focuses on creative and UX experiments that move performance.
For example, recent creative analysis showed that something as small as repositioning a popup CTA button or recommending a different image could swing efficiency by 2 percentage points or more. Those insights flow straight back to the AdControl team and end up shaping the ad products themselves.
What are your most popular ad products — and any new ones launching?
The flagship product is the full-screen popup that fires on app launch, with an average CTR of around 5%. It's almost always sold out. Rather than just opening more inventory to keep up, we asked a different question: how do we help advertisers hit a different marketing objective? Popups maximize traffic; video, we figured, could deliver the branding objective. So we built a video ad product together with Adrop. Thanks to how fast Adrop could move, we shipped it quickly — and the first campaign was fully booked before launch.
Our main popup is always sold out — fill rate 100%. So we introduced video ads to absorb the rest of the advertiser demand.
What's the secret to keeping advertisers happy?
We think from the advertiser's point of view at work, from the user's point of view at home, and we improve efficiency with data.
- At work, think like an advertiser. Our team's goal is for advertisers to never feel their budget was wasted on Mamitalk — we measure ourselves on hitting their objectives, not just on our revenue. Working alongside them to push performance up is the part advertisers say they appreciate most.
- At home, think like a user. Users have to find the ad easy to look at and worth being interested in before efficiency can climb. So we sweat UI/UX from the user's side, and we lean on precise targeting to deliver user-matched advertising. That ends up directly improving performance.
- Improve efficiency with data. The team runs a constant experiment → analyze → feedback loop. Even when this campaign is performing well, we're already asking how we can make next month's run more efficient.
Epilogue
Mamitalk's ad business started with a team that had zero advertising experience. Through org redesign, data-driven experimentation, and tight collaboration with the product team, they ended up with an industry-leading 80% advertiser re-booking rate. The lesson: any team with a solid platform and the right advertiser relationships can build advertising into a real growth engine.
Editor: Jensen
Published: 2025.09.29