What drives a product's viral, word-of-mouth growth?

Noam Shazeer · Aug 31, 2023

Character's growth came from simply launching, launching something general, and meeting a massive existing need — billions of people feel they need someone to talk to.

A general product plus real unmet need means users will find it; the key unlock was actually shipping.

9:46 20VC: Spending $2M to Train a Single AI Model: What Matters More; Model Size or Data Size | Hallucinations: Feature or Bug | Will Everyone Have an AI Friend in the Future & Raising $150M from a16z with Noam Shazeer, Co-Founder & CEO @ Character.ai

Guillaume Cabane · Nov 29, 2023

True virality — a huge market plus a very sticky viral product — creates growth opportunities unlike anything else, because customers acquire customers at no cost

He knows the leaders at Dropbox and Zapier and how they pulled it off; compared to his own hard-work approach, having a million people invite themselves in a month is unmatched

Scope: he has never had the chance to run this playbook himself

60:12 20Growth: The Golden Rule to $100M in ARR, Why CAC to LTV is BS Early On, Why Your First Growth Hire Should Be a Former Founder & How Ramp Does 200 Growth Experiments Per Quarter with Guillaume Cabane

Andy Rachleff · Mar 10, 2017

People confuse network effects with virality; they are distinct, and delight drives virality independently of any network effect

Netflix, Google and Apple products have no network effect, yet users love them and tell all their friends

10:46 20VC: Wealthfront and Benchmark's Andy Rachleff on Why Delight Is The Greatest Form Of Virality, Why Competition Does Not Matter & What The Future Holds For Automated Personal Finance

Fabien Pinckaers · Feb 12, 2025

Word-of-mouth is Odoo's main acquisition channel, and it only works if the product is strong enough to turn users into fans

Very happy clients talk to other clients and bring them in; that requires a product capable of creating fans

17:38 20VC: The $5BN Company Built from the Belgian Countryside | The Story of Odoo: The Company with No Plans to Sell, IPO & Their Billionaire Founder Who Does Not Care About Money with Fabien Pinckaers, Founder & CEO @ Odoo

Aman Narang · Aug 21, 2024

Restaurant sales compound through micro-level local density: as you win more restaurants on a street or in a neighbourhood you get better word of mouth, more referrals, more top of funnel, higher conversion and faster growth

Restaurants cluster on every street corner, and the data showed the flywheel operating at a hyper-local rather than city-wide level

Scope: pattern first spotted by head of revenue Jonathan Bassemer; obvious only in hindsight

38:26 20VC: Five Lessons Scaling Toast to $14BN Market Cap | The Biggest Mistakes Founders Make in Fundraising, Hiring and Selling with Aman Narang, CEO @ Toast

Mike Hudack · Sep 13, 2024

The right go-to-market path is to cozy up to small communities, build deep relationships, find sparks of success, double and triple down on them, and spread virally outward

25:33 20Product: What Facebook, Monzo and Deliveroo Do and Do Not Do To Build Great Products | How to Structure Product Teams For Success | Is Simple Always Better in Product and The Art vs Science of Product Design with Mike Hudack

Harry Stebbings · Jun 10, 2024

TikTok is not really a social network but was, in its early days, a case of very effective paid marketing

Scope: about the early days

71:46 20VC: Reid Hoffman on Foundation Models: Who Wins & How Do Incumbents Respond | The Inflection AI Deal: How it Went Down | Why Trump is a Threat to Democracy | The Future of TikTok | Lessons from Sam Altman, Brian Chesky and the OpenAI Board

Cliff Weitzman · May 9, 2026

Word-of-mouth remains the largest acquisition channel even for a company running thousands of paid ads a day, and paid channels are valuable partly for their halo effect on it

The more the message is out there in different ways, the more seeds are sown for people to tell each other about the product

Scope: Meta is the best-performing paid channel, Google the most profitable

28:13 20VC: What I Learned from 100 of the Best CEOs in the World | What I Learned from Staying with Mr Beast for 3 Weeks | How We Will Spend More on Tokens than Salaries with Cliff Weitzman, Speechify

Raman Malik · Nov 15, 2024

AI companies get a large volume of curiosity traffic — anything with a magical demo will get traffic and quick usage — and organic word-of-mouth is the best acquisition channel a company can have.

Perplexity is two years in and still riding a wave of organic traffic, which is why the job is to keep nurturing it.

17:37 Ai products with magical demos generate curiosity traffic and organic word of mouth is the best channel

Raman Malik · Nov 15, 2024

Perplexity has no inherent viral loop — sharing isn't native to the user journey — yet a lot of traffic already arrives through user sharing, making in-product sharing the biggest missed opportunity

Users already screenshot answers or post threads to Twitter and that drives meaningful inbound traffic, so deliberately designing for sharing should compound it

42:39 Undesigned organic sharing already drives traffic so deliberate in product sharing is the biggest missed opportunity

Raman Malik · Nov 15, 2024

Building products or features designed for viral sharing is the fastest route to growth

Something highly shareable or unique makes users distribute it for you, as Spotify Wrapped showed and as many AI startups now copy

55:41 Designing for viral sharing as a feature is the fastest growth route

Harry Stebbings · Jan 18, 2023 · hedged

ChatGPT's growth resembles a UGC loop, in that user inputs generate the outputs that drive further usage, even though it isn't literally user-generated content

47:24 Chatgpts input output usage loop functions like a ugc loop driving word of mouth growth

Severin Hacker · May 19, 2025

Having zero marketing budget was an advantage because the constraint forced Duolingo to generate ideas rather than buy attention

With no revenue and no profit they couldn't spend money they didn't have, and the constraint was very good at forcing good ideas — the mascot, costumes and unhinged self-mocking content

42:39 Budget constraint forces organic creative growth tactics

Mike Hudack · Sep 13, 2024

Sling will launch with viral, word-of-mouth growth rather than paid marketing

Early users are returning, using it a lot and giving great feedback — if the product is really great people will tell their friends

22:02 Launch via organic word of mouth rather than paid marketing

Reid Hoffman · Jun 10, 2024

TikTok's followerless, algorithmically matched feed was a genius invention forced by necessity, since the Chinese government barred social networks with more than 500 followers

Unable to use a connection or follower graph like LinkedIn or YouTube, they paid for content creation at scale and then used engagement signals — seconds watched, swipes — to match users to a flow of current content, which produced a scale effect

72:04 Algorithmic followerless feed design was the genius innovation behind viral growth

Matan Bar · Feb 11, 2021

B2B payments cannot use the closed-network virality of P2P apps; forcing vendors to sign up in order to be paid would destroy the value for the paying business

A restaurant paying 15 suppliers must be able to pay each of them, including a supplier who only accepts checks and will never join Melio; otherwise the payer's core need goes unmet

9:34 Open one sided network beats forced signup virality