Viral Marketing: Definition, What Makes Content Spread, and 10 Real Examples With Their Lessons

Viral marketing borrows its name from epidemiology: a message passes from one person to the next like a virus. The term spread in the late 1990s; Wikipedia's article on viral marketing traces it to Jeffrey Rayport's 1996 Fast Company piece "The Virus of Marketing" and to investors Tim Draper and Steve Jurvetson, who used it in 1997 to describe Hotmail's growth. Since then, social networks have made sharing instant, but the reasons people share have barely changed.

What is viral marketing?

Viral marketing covers any action designed so that the audience distributes the message. Three forms coexist:

It overlaps with word of mouth, influencer marketing and grassroots marketing, but differs in one point: the brand does not pay for each new person reached. That is why a viral success can bring reach no media budget could buy, and why it is impossible to guarantee.

Why do people share content?

The most cited research on the question comes from Wharton professor Jonah Berger. In "What Makes Online Content Viral?" (Journal of Marketing Research, 2012), Berger and Katherine Milkman analyzed nearly 7,000 New York Times articles. Positive content was shared more than negative content, but physiological arousal mattered more than valence: content evoking awe, anger or anxiety was more viral, while content evoking sadness, a low-arousal emotion, was less viral. Surprising, interesting and practically useful content was also shared more.

In his book Contagious (2013), Berger summarized six drivers under the acronym STEPPS, presented by Knowledge at Wharton:

10 real examples of viral marketing

1. Hotmail: the footer that recruited users (1996 - 1997)

Every email sent from Hotmail ended with "Get your free e-mail at Hotmail". According to Wikipedia, the service signed up 12 million users in 18 months. Lesson: the most reliable virality is built into the product, so that every use is an invitation.

2. Blendtec, "Will It Blend?"

Blendtec filmed its blender shredding objects such as an iPhone. Berger notes that the campaign started with a $50 budget and made a dull product remarkable. Lesson: a spectacular demonstration of a real product benefit is shareable and selling at the same time.

3. Old Spice, "The Man Your Man Could Smell Like" (2010)

Launched online on February 4, 2010, the ad was followed by a series of personalized video replies to people on social media. In mid-July 2010, videos from the series held eight of the eleven most popular videos on YouTube, according to Adweek as cited by Wikipedia, and the ad won the Film Grand Prix at Cannes Lions and an Emmy. Lesson: replying fast and personally to the audience turns a good ad into a conversation.

4. Dollar Shave Club launch video (2012)

Posted on March 6, 2012, the founder's low-budget, funny video brought 12,000 orders in the first 48 hours. Unilever acquired the company in 2016 for a reported $1 billion. Lesson: humor works when it carries a clear value proposition, here a cheaper subscription to razor blades.

5. Dove Real Beauty Sketches (2013)

A forensic artist drew women first from their own description, then from a stranger's. Released on April 14, 2013, the films passed 163 million global views by June and won the Titanium Grand Prix at Cannes. Lesson: an emotional truth that viewers recognize in themselves is shared as a statement, not as an ad.

6. Movember

Men grow a mustache in November to raise funds and awareness for men's health. Berger uses it as the example of the "public" principle: a private donation becomes visible on every participant's face. Lesson: make support visible and it recruits the next participant.

7. ALS Ice Bucket Challenge (2014)

Participants poured ice water on their heads, filmed it and nominated three people. The ALS Association passed $100 million in donations by August 29, 2014, and in 2016 it announced that research partly funded by the challenge had identified a new gene linked to ALS, NEK1. Lesson: a simple, filmable action plus a nomination mechanism creates participation virality.

8. Spotify Wrapped

Each December, Spotify gives users a personal summary of their year in listening, designed for sharing on social networks. According to Spotify's fourth quarter 2025 earnings release, the 2025 edition had more than 300 million engaged users and more than 630 million shares on social media in 56 languages. Lesson: personal data turned into a flattering story is social currency that users happily distribute.

9. Wordle (2021 - 2022)

The daily word game added a grid of colored squares that let players share their result without spoiling the answer. Players rose from about 90 on November 1, 2021 to more than 300,000 on January 2, 2022, and The New York Times bought the game that month for a "low seven-figure sum". Lesson: a share format that shows off the result while keeping curiosity intact drives growth with no advertising.

10. Burger King, Subservient Chicken

A website showed a person in a chicken costume who obeyed typed commands. Berger notes that the light branding made people share it as entertainment rather than as an ad. Lesson: playfulness and interactivity travel, as long as the link to the brand stays clear enough to benefit from it.

What can you reproduce in your own marketing?

Ideas for everyday posts that use the same mechanisms are listed in our social media content ideas, and our guide to video marketing strategy helps turn them into a plan. On TikTok, the recommendation system decides how far a video travels; our article on the TikTok algorithm explains how.

How do you measure viral marketing?

• Share rate: shares divided by views or recipients, the most direct signal.
• Viral coefficient (K-factor): average number of new users each user brings. Above 1, growth feeds itself; most campaigns stay well below.
• Earned reach: impressions you did not pay for, compared with paid reach.
• Branded search: growth in searches for your brand name in Google Search Console, a sign that attention turned into intent.
• Business results: sign-ups, orders or donations during and after the peak.

The last two matter most: a campaign that is shared widely but leaves no trace in searches or sales has built brand awareness at best. The growth marketing approach treats virality as one loop among others, tested and measured like the rest.

What are the risks?

• Loss of control: once shared, the message can be mocked, remixed or turned against the brand.
• Off-target audience: millions of views from people who will never buy.
• Short life: a peak of attention that fades within days without a follow-up.
• Backlash: humor or provocation that offends can spread faster than the original message.

Viral marketing, SEO and GEO

A viral moment leaves durable traces when it creates links and mentions. Media coverage of a campaign earns backlinks, which our guide to digital PR shows how to provoke, and discussions on Reddit, YouTube or LinkedIn become sources that ChatGPT, Gemini and Perplexity quote; our social media AI citation study measures how often. Shares themselves, the social signals, are not a direct Google ranking factor, but the searches and links they cause are.

To keep the attention once the peak is over, the brand needs pages that answer the searches the campaign provoked. Sorank writes and publishes those articles in autopilot with its blog article generator, and AI mention tracking shows whether AI assistants start citing your brand.

The essentials

Virality is not luck, but it is not a recipe either. Design something people want to be seen sharing, make sharing effortless, then measure whether the attention turns into searches, links and sales. The most reliable form is the one built into the product itself; campaigns add peaks, and search keeps what the peaks bring.