How Duolingo rolled out ads thoughtfully

On the podcast, I talk with Cem about the premium trap many apps fall into, why free trials work even for freemium products, and how ‘try for $0.00’ actually outperforms ‘try for free’.

Top Takeaways:

💡 Protect the free moat — always
 Short-term revenue tricks like paywalling free features make metrics spike — then stall. Sustainable freemium growth depends on preserving free value. It’s not just ethical; it’s strategic. Pulling back too much invites competitors to offer what you took away, weakening both your brand and your growth loop.

🧪 A/B test relentlessly — but know when to lead with intuition
 Testing is essential, but not infallible. With 400+ experiments running at once, you’ll often see trade-offs between revenue and user experience. The art of product management is knowing when to ignore short-term data and make the long-term call that preserves user trust and helps achieve strategic goals.

🔁 Freemium is a growth engine, not a trade-off
 Your free users aren’t freeloaders — they’re your marketing engine. When you improve the free experience, you strengthen organic growth through word of mouth. Growth slows when you nickel-and-dime; it compounds when you delight.

💰 Monetize with empathy, not extraction
 Introducing monetization requires a cultural shift. The key is measuring everything — retention, reviews, complaints per DAU — and optimizing for user experience, not just ARPU. Test cautiously, communicate transparently, and say no to anything that erodes trust.

🧠 Build for everyone, not a persona
 In large-scale apps, personas can be counterproductive. People learn, play, and engage for wildly different reasons. Designing for inclusivity and broad appeal helps scale from millions to billions of users without alienating key segments.

💡 Strategic and Creative Use of Ads
 Ads at Duolingo were introduced carefully with the goal of balancing monetization with a positive user experience. The focus is on surfacing ads at non-intrusive moments, such as after completing a lesson, and on carefully controlling ad content. Duolingo even partners with advertisers to integrate elements of Duolingo branding into third-party ads. 

About Cem Kansu:

🚀Chief Product Officer at Duolingo

📱 Cem Kansu is the former VP of Product at Duolingo, where he led the company’s monetization strategy, introducing ads and subscriptions that turned Duolingo into a sustainable business. With deep expertise in product development and user experience, he helped grow subscriptions to over 80% of revenue, while keeping the core product free and mission-driven.

👋 LinkedIn

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Episode Highlights:
[0:00] Cem discusses balancing profitability with long-term goals

[0:36] Duolingo’s first monetization strategy: ads

[2:02] The pivot from crowdsourcing translations to new monetization models

[3:49] Streak repair as Duolingo’s first in-app purchase experiment

[5:43] Shifting company culture to embrace monetization

[7:20] The influence of investors on Duolingo’s monetization

[8:00] Introducing ads without harming user experience

[10:31] Handling user complaints and data-driven adjustments

[12:07] Ensuring ad quality through strict control

[13:53] Direct ad partnerships to improve user experience

[16:30] Ads vs subscription: monetization strategy decision

[18:43] The impact of free trials on subscription growth

[20:22] Evolution of Duolingo’s subscription offerings

[22:39] Adding features like offline learning and ad-free experiences

[24:22] Pivoting from separate apps to integrating topics in one

[26:43] Overcoming design challenges to fit new topics

[28:55] Duolingo’s competition with other screen time apps

[32:00] Leveraging AI to enhance the language learning experience

[35:18] The role of AI in Duolingo’s growth

[37:32] Balancing free vs paid features for growth

[40:24] Decisions on adding/removing premium features

[43:35] Lessons from the failed human tutor feature

[45:10] Challenges in scaling a large product like Duolingo

[47:12] Long-term growth focus and user base expansion

[49:30] Design, testing, and iteration at Duolingo

[54:10] Ongoing improvements in learning efficacy and retention

[57:15] Duolingo’s future plans and expansion goals