The library · free
Everything three classic books teach about making products people love.
28 true stories, 194 lessons and 46 real company cases from Actionable Gamification, Influence and Hooked. Open any card to see what it is, why it works and how to build it in your app.
How to read it
Every product is a journey. Each book helps at a different step.
The 8 Core Drives explain why people do anything at all. The principles of Influence shape the moments people decide. The Hook turns repeated use into a habit. Gamify It finds the step where your product can grow most and picks the lessons that fit it.
- 01ValuePeople really need it.
- 02DiscoverThe right people find it and try it.
- 03StartNew users get a first win, fast.
- 04ReturnThey come back on their own.
- 05StayRegulars stay for months.
- 06PayHappy users choose to pay.
- 07SpreadFans bring their friends.
Journey
28 stories, 194 lessons and 46 real company cases.
Start with the stories28
True stories from the books, each with the lesson behind it.
Actionable Gamification · Yu-kai Chou
The 8 Core Drives
The eight reasons people do anything, from feeling part of something bigger to not wanting to lose what they have.
Epic meaning5
People do more, and forgive more, when they feel part of something bigger.
Accomplishment15
People love to see themselves get better, and they hate leaving progress unfinished.
Creativity and feedback9
People stay when they can make things their own way and see the result right away.
Ownership7
Once something feels like ours, we value it more and want to keep making it better.
Social influence13
We care what others do and think, and we measure ourselves against people like us.
Scarcity and impatience10
We want most what we can’t have yet, or can only have for a short while.
Curiosity5
Not knowing what comes next pulls us in. A small surprise beats a sure thing.
Loss and avoidance12
We work hard to avoid losing what we have, but only when we can see how.
More from Actionable Gamification4
Techniques that mix several drives, or set the stage for all of them.
Influence · Robert Cialdini
The 6 principles of influence
The mental shortcuts that make people say yes, and how to use them honestly at the moments people decide.
Reciprocity7
When someone gives us something first, we want to give something back.
Commitment and consistency11
Once we say yes to something small, we want our next steps to match it.
Social proof8
When people aren’t sure what to do, they do what they see others doing.
Liking7
We say yes more easily to people we know and like.
Authority5
We follow people who clearly know their stuff, even more when they’re honest with us.
Scarcity6
Things seem more valuable when they are rare or about to run out.
Contrast and honest cues8
What we see first changes how we judge what comes next, and every cue has to be true to keep working.
Hooked · Nir Eyal
The Hook
How a product becomes a habit: a trigger, an easy action, a reward that varies, and a small investment that brings people back.
Trigger16
A reminder brings people back at first. Later, a feeling they already have does it.
Action18
People act when it’s easy, they want to, and something prompts them, all at once.
Variable reward11
People come back for rewards that change every time: likes, new finds, small wins.
Investment11
The more people put into your app, the more it’s worth to them, and the more they return.
More from Hooked6
How to tell if your product can become a habit, and how to test it.
Real company cases46
What happened when real products used these ideas, with the numbers they reported.
- Airbnb2017Airbnb: reputation beats similarityAirbnb has to get strangers to trust each other. A Stanford and Airbnb study with 8,906 users found that strong reputation signals made people trust hosts unlike themselves, a result consistent with about 1M real Airbnb…Read the case
- Amazon2025Amazon Prime: easy to join, hard to leaveAmazon removed friction from buying and from joining Prime. The FTC alleged it also enrolled people without clear consent and made cancelling deliberately hard.Read the case
- Apple (Apple Watch)2024Apple Watch: permission to restApple Watch's Activity rings reward closing Move, Exercise and Stand goals every day, with streaks. watchOS 11 (2024) added Pause Rings: rest for a day, a week, a month or up to 90 days without breaking the streak.Read the case
- Booking.com2019Booking.com: urgency claims meet regulatorsBooking.com and other hotel sites used banners like “only 1 room left” and “N people are looking”. In 2019 the UK competition regulator got six sites to stop false impressions of availability or popularity, and EU…Read the case
- Canva2025Canva: instant competence, templates firstCanva's onboarding asks what you are making and starts you from a template, with drag-and-drop editing and a generous free tier, so a first-time user produces something that looks good within minutes.Read the case
- Dropbox2010Dropbox: a referral reward that is the productDropbox gave free storage to both the inviter and the new user, shown next to the paid upgrade: invite friends or pay. Chou calls the pairing Anchored Juxtaposition.Read the case
- Duolingo2023Duolingo: weekly leaguesDuolingo added weekly XP leagues where learners compete with a small group of peers and are promoted or demoted between tiers.Read the case
- Duolingo2020Duolingo: smarter reminders, not more remindersDuolingo used a bandit algorithm to choose the wording of each daily practice reminder while holding notification volume flat.Read the case
- Duolingo2022Duolingo: a streak with a safety valveDuolingo made the daily streak its core return mechanic, then let learners equip Streak Freezes that protect the streak on a missed day.Read the case
- Duolingo2026Duolingo: the Streak Revival eventIn June 2026 Duolingo ran a one-time event: lapsed learners could restore their longest-ever streak by opting in and finishing three lessons.Read the case
- eBay2015eBay: auction countdowns and seller starsChou reads eBay through Octalysis: auction countdowns create urgency, bidding makes buyers chase a win, and seller stars and Power Seller status reward accumulation.Read the case
- Evernote2011Evernote: paying grew with tenureEvernote's CEO Phil Libin showed usage dipping after sign-up and then rising as habits formed, with the paying share rising with tenure: about 0.5% after month 1, 11% by month 33 and 26% at month 42.Read the case
- Facebook (Meta)2004Facebook: exclusivity that became identityFacebook launched only for Harvard students and opened school by school. Chou reads this as Scarcity in the Discovery phase: being let in felt like belonging.Read the case
- Facebook (Meta)2016Facebook: 7 friends in 10 daysFacebook's growth team compared users who stayed with users who left and found a setup milestone: reaching 7 friends within 10 days. Onboarding was then aimed at connecting new users fast.Read the case
- Figma2025Figma Community: remix cultureFigma lets anyone publish files, UI kits, plugins and widgets that others can duplicate and remix, and since 2022 creators can sell them.Read the case
- Google2015Google: more ads taught users to ignore adsGoogle ran long-running experiments on search ads and found users learn: after seeing low-quality ads they become less willing to click any ads.Read the case
- Google2014Google Search: a habit rivals couldn't breakHooked uses Google Search to show how a frequent, useful behavior becomes a default: rivals of similar quality struggle because switching means relearning.Read the case
- 24 Hour Fitness (megastudy)2021The gym megastudy: most effects didn't lastThirty scientists designed 54 four-week programs to get 61,293 members of a US gym chain to work out more. About 45% raised weekly visits while they ran, but only about 8% still showed an effect after they ended, and…Read the case
- Hotel field experiment (Goldstein, Cialdini & Griskevicius)2008The hotel towel study: “guests in this room”Goldstein, Cialdini and Griskevicius tested hotel cards asking guests to reuse towels. Saying most guests reuse their towels beat the standard environmental appeal, and the norm of guests who had stayed in the same room…Read the case
- Instagram (Meta)2021Instagram: hiding likes, then letting people chooseInstagram tested hiding public like counts from 2019 to see whether it eased social pressure. In May 2021 Meta made it optional on Instagram and Facebook: hide counts on others' posts, on your own, or keep them.Read the case
- LinkedIn2015LinkedIn: invitations sent in your nameLinkedIn's Add Connections imported members' contacts and emailed them invitations, followed by two automatic reminders using the member's name. A class action argued members had not agreed to the reminders.Read the case
- LinkedIn2012LinkedIn: the profile strength meterLinkedIn's profile meter shows how complete your profile is and starts new members with some progress already filled in. Hooked and Actionable Gamification both use it as a progress example.Read the case
- Match Group (Tinder, Hinge)2026Tinder vs Hinge: variety vs investmentTinder's swipe is a near-effortless variable reward; Hinge asks people to build profiles with prompts that others reply to. In Q2 2026, Match Group's payers fell 6% while Hinge grew revenue 22% and monthly users 13%.Read the case
- Mercado Libre2026Mercado Libre: seller reputation as currencyMercado Libre shows each seller's reputation as a red-to-green thermometer built from claims, late shipments and cancellations, with MercadoLider status on top. Its loyalty program became the paid MELI+ subscription.Read the case
- Mint (Intuit)2024Mint: stored value didn't save itHooked praised Mint for a clear one-button external trigger and for linked bank accounts, stored value that makes the app more useful over time. Intuit shut Mint down on March 23, 2024 and moved users to Credit Karma.Read the case
- Notion2024Notion: templates as investment and communityNotion relaunched its Template Gallery as a marketplace with creator profiles. In the prior year, templates were duplicated 51M times by nearly 11M people, and the gallery grew from about 600 to more than 5,000…Read the case
- Opower2014Opower: your energy use vs your neighbors'Opower mailed home energy reports comparing each household's use with similar neighbors, with praise for efficient homes and tips.Read the case
- Peloton2026Peloton: loyal members, shrinking top of the funnelPeloton's live leaderboards, milestones and instructor shout-outs keep owners subscribed: average monthly churn was 1.7% in fiscal 2026.Read the case
- Penn Medicine (STEP UP trial)2019Penn STEP UP: competition beat support and collaborationA Penn Medicine randomized trial gave 602 adults wearables plus a game with points, levels and loss-framed scoring, in support, collaboration or competition arms.Read the case
- Pinterest2026Pinterest: Hooked's textbook example, then and nowHooked walks through all four phases of the Hook with Pinterest: infinite scroll, a feed of variable objects of desire, and pins that train the feed and earn the next notification.Read the case
- Pokemon GO (Niantic)2016Pokemon GO: the extra steps fadedPokemon GO turned walking into a hunt. A BMJ study of 1,182 US adults found players walked 955 more steps a day in their first week, but the boost faded week by week and was back to baseline by week 6.Read the case
- Fashion retailer (study) vs the Amazon claim2018Product recommendations: the 35% claim vs a controlled testA widely repeated estimate says recommendations drive 35% of Amazon's purchases. When researchers switched recommendations on and off in a large experiment on a major fashion retailer's site, overall sales rose about…Read the case
- Robinhood2024Robinhood: confetti on tradesRobinhood celebrated trades with confetti and offered free-stock “scratch card” rewards. It removed the confetti in 2021 amid scrutiny.Read the case
- Slack2015Slack: the 2,000-message thresholdSlack treated a team that had exchanged 2,000 messages as a team that had really tried the product, and steered onboarding (invites, integrations) toward that point.Read the case
- Snapchat (Snap Inc.)2025Snapchat: Snapstreaks and a state lawsuitSnapstreaks count the consecutive days two friends snap each other; since 2023 a broken streak can be restored, with extra restores sold.Read the case
- Spotify2025Spotify Wrapped: identity as a rewardEvery December Spotify turns a year of listening into a shareable recap of top artists, genres and minutes. Wrapped 2025 reached 200M+ engaged users in its first 24 hours and 500M+ shares on day one, per Spotify.Read the case
- Stack Overflow2025Stack Overflow: when instant answers beat pointsHooked's example of rewards of the Tribe: points and badges that earned Stack Overflow thousands of answers a day. Prosus bought it for about $1.8B in 2021.Read the case
- Starbucks2025Starbucks Rewards: stars, tiers and devaluation riskStarbucks Rewards pays Stars per dollar, with personalized challenges and mobile ordering. At the end of fiscal 2025, 34.2M US members were active over 90 days and their spend was 58% of tender in US company-operated…Read the case
- Strava2025Strava: one-tap kudosStrava lets athletes give one-tap kudos on each other's activities, alongside segments, clubs and an annual Year in Sport report. Its 2025 report counted 14B kudos given across a community of about 180M people.Read the case
- Superhuman2018Superhuman: 22% to 33% without shipping a featureSuperhuman asked users how they would feel if they could no longer use the product. Only 22% said very disappointed.Read the case
- TikTok2024TikTok Lite: paid to watch, then withdrawnTikTok Lite's Task and Reward program, launched in Spain and France in April 2024, gave points for watching videos, liking, following and inviting friends.Read the case
- TOMS2019TOMS: One for One, retiredTOMS promised to give a pair of shoes for every pair sold; Chou cites it as White Hat reassurance that turns a purchase into a contribution.Read the case
- Twitter (now X)2017Twitter: follow about 30 accountsTwitter's growth team found that new users who followed about 30 accounts became long-term users, and improved how it suggested people to follow.Read the case
- Waze2013Waze: drivers fighting the traffic monsterWaze framed traffic reports and map fixes as a shared fight against traffic, so drivers volunteered corrections without pay. Chou uses it for Epic Meaning and for a full four-phase Octalysis analysis.Read the case
- YouVersion (Bible App)2025YouVersion: an ethical habit at a billion installsHooked's case study: the Bible App grew through reading plans chunked into daily portions, a cascade of reminders users choose, and easy, engaging content first. It had 100M downloads in 2013;Read the case
- Zynga2012Zynga and FarmVille: the Black Hat reboundFarmVille drove huge engagement with appointment mechanics, requests to friends and the fear of losing crops. Hooked notes Zynga's value fell more than 80% from its peak as its rewards became predictable;Read the case
