Contagious

Word-of-Mouth & Virality Framework

A framework for engineering word-of-mouth and making products, ideas, and content contagious, based on Jonah Berger's research into why things catch on. Use it to design shareability into products, campaigns, and content instead of hoping for luck.

Core Principle

Virality is not born — it is engineered. Products spread because they were designed — consciously or not — to be shared. Only 7% of word-of-mouth happens online; the other 93% happens in offline conversations, so virality is about the psychology of sharing, not social media mechanics. Those psychological patterns are predictable and can be engineered into anything using the STEPPS framework.

See: references/word-of-mouth.md when the brief over-indexes on social media — it makes the offline-vs-online case, lists conversation triggers, and gives a WOM measurement/audit method.

Scoring

Goal: 10/10. Score each of the six STEPPS drivers (the six Quick Diagnostic rows) — 0 absent, 1 present but weak, 2 strong and deliberate — for a raw 0-12, then map: 11-12 -> 10, 9-10 -> 8-9, 6-8 -> 6-7, 3-5 -> 4-5, 0-2 -> <=3. Bands:

• 9-10 — three or more drivers at strength 2, at least one of them Public or Social Currency (the self-propagating ones), and the brand survives the Trojan Horse test.
• 6-8 — two drivers genuinely strong, but spread still leans on paid reach or product quality alone.
• <=5 — at most one weak driver; sharing is incidental, not engineered.

Report the raw count, the mapped score, and the specific driver(s) to raise next to reach 10/10.

STEPPS Overview

Not a checklist — a multiplier. Each principle independently increases sharing; the most contagious ideas activate several at once, but even one or two done well dramatically increase word-of-mouth.

The STEPPS Framework

1. Social Currency

Core concept: People share things that make them look good — smart, cool, in-the-know. Make people feel like insiders and they'll spread it to boost their own image.

Why it works: Sharing is self-presentation — listeners infer the sharer's traits from what they pass on, so people curate shares the way they curate clothes. Mechanism: give the sharer a payoff in status or identity and you outsource your marketing to their ego.

Key insights:

• Remarkability — surprising, novel, or extreme things make the sharer seem interesting; "Did you know...?" is a powerful sharing trigger
• Game mechanics — leaderboards, badges, and status tiers create visible accomplishments people want to display
• Exclusivity and scarcity — secret menus and invite-only access give people "insider knowledge" to share
• Inner remarkability — even mundane products have a remarkable angle; it's framing, not the product

Product applications:

Copy patterns:

• "Most people don't know that..."
• "You're one of the first to try..."
• "You've unlocked [achievement]..."

Ethical boundary: Create real insider value, not false scarcity or manufactured exclusivity that breeds toxicity.

See: references/social-currency.md when a product feels unremarkable — it has the inner-remarkability exercise, game-mechanic design, exclusivity types, and a scored audit.

2. Triggers

Core concept: Top-of-mind means tip-of-tongue. Link your product to environmental cues — sights, sounds, times, routines — so everyday life keeps reminding people to talk about you.

Why it works: Most word-of-mouth is driven not by excitement but by whatever happens to be top-of-mind mid-conversation; a product linked to a frequent cue gets mentioned more because it's more accessible in memory.

Key insights:

• Frequency beats strength — a daily trigger (coffee) outperforms a powerful but rare one (a holiday); Kit Kat linked itself to coffee breaks
• Habitat matters — map where and when people encounter contexts related to your product
• Competitive triggers — link a competitor's moment to your own brand
• Ongoing vs. temporary — persistent environmental triggers sustain word-of-mouth; event triggers only spike it

Product applications:

Copy patterns:

• "Every time you [frequent activity], think of..."
• "Next time you [daily habit]..."
• "It's [day/time] — time for..."

Ethical boundary: Build genuine, helpful associations — hijacking sensitive contexts (grief, health scares) as triggers backfires.

See: references/triggers.md when picking a cue to attach to — it has the habitat-analysis worksheet, the frequency matrix, and the 4-step trigger design process.

3. Emotion

Core concept: When we care, we share. High-arousal emotions — positive (awe, excitement, amusement) or negative (anger, anxiety) — drive sharing; low-arousal emotions (sadness, contentment) suppress it.

Why it works: Physiological arousal — racing heart, activated state — creates a need to share. It's activation vs. deactivation, not positivity vs. negativity.

Key insights:

• High-arousal drives sharing: awe, excitement, amusement, inspiration, anger, anxiety
• Low-arousal suppresses it: contentment and relaxation feel no urgency; sadness makes people withdraw
• Awe is the most powerful sharing emotion — feeling small before something vast or surprising spreads furthest
• Emotional framing — the same facts can be framed for different arousal levels; facts inform, framing motivates sharing

Product applications:

Copy patterns:

• "I can't believe [surprising fact]..."
• "Watch what happens when..."
• "This will change how you think about..."

Ethical boundary: Engineering outrage for clicks corrodes trust — use high-arousal negative emotion sparingly and only when the cause genuinely warrants it.

See: references/emotion.md when content feels flat — it has the emotion-sharing matrix, awe-engineering techniques, and humor design rules.

4. Public

Core concept: Built to show, built to grow. If people can see others using your product, they're more likely to adopt it — design for observability.

Why it works: Visible choices resolve uncertainty for the observer — seeing others use a product lowers their perceived risk and supplies social proof at zero marginal cost, so observability turns each user into a passive, continuous billboard.

Key insights:

• Behavioral residue — design visible traces that outlast use: a Livestrong wristband long outlives the donation
• Self-advertising products — every Hotmail email carried "Get your free email at Hotmail"; the product marketed itself through use
• Public = imitable — people can only copy what they can observe; find ways to make invisible usage visible

Product applications:

Copy patterns:

• "Show the world you [achievement/identity]..."
• "Share your [output] — powered by [brand]..."
• "Join [number] others who..."

Ethical boundary: Visibility must empower, never shame — users always control what becomes public, and private data (failures, health, finances) stays private.

See: references/public-visibility.md when usage is invisible — it has the public-vs-private breakdown, the behavioral-residue design checklist, and the Apple-logo design lesson.