📂 The story behind the world’s most successful slogan

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In 1947, the slogan “A Diamond Is Forever” was crafted by an ad agency to create the concept of diamonds as essential for engagement.

But before the 20th century? That wasn’t a thing. It wasn’t tradition. It wasn’t even expected.

Diamonds weren’t rare, they weren’t in high demand, and they weren’t selling. That all changed when De Beers, a struggling mining company, launched one of the most successful marketing campaigns of all time.

It didn’t just sell diamonds — it made diamonds essential.

Samuel Jefferies @MrSamLJ Until World War 2 only 10% wore diamond engagement rings. Today that figure is 84%. This is the insane story of how one company pulled off one of the greatest marketing campaigns the world has ever seen. Diamonds - The colonialist's dream. A thread 👇👇👇 5:55 AM • Jul 6, 2021 694 Retweets 1734 Likes Read 17 replies

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What diamonds can teach you about demand

By the 1930s, diamond sales were in freefall. The Great Depression hit, and De Beers needed a way to get people to buy more diamonds. The problem? People didn’t see them as valuable or necessary.

So, they created the perception of value.

They hired ad agency N.W. Ayer & Son, who had one job: make diamonds feel rare, meaningful, and non-negotiable. At their offices in 1947, copywriter Frances Gerety wrote four words that would reshape history:

“A Diamond is Forever”

It was brilliant — by linking the durability of diamonds to the idea of eternal love, they became a lifelong symbol of commitment.

De Beers didn’t stop at ads. They controlled supply to create artificial scarcity, paid celebrities to wear diamonds, and embedded them in pop culture through Hollywood films.

By the 1950s, diamonds had cemented their place in culture, woven into Hollywood, fashion, and romance itself.

Marilyn Monroe sealed the deal in Gentlemen Prefer Blondes, singing “Diamonds Are a Girl’s Best Friend” in one of the most iconic performances in film history.

The message was clear: if you were in love, a diamond was the only way to prove it.

Today, 84% of engagement rings feature diamonds. Not because they’re rare. Not because they’re the best choice. But because De Beers made sure that’s what people believed.

What SaaS can learn from this

There’s more to this story than just a history lesson — it’s a masterclass in shaping demand. The best SaaS companies don’t just enter a market; they define it. Here’s how:

1. Category creation: Without De Beers’ marketing, diamonds wouldn’t be the default for engagement rings — they transformed a preference into an expectation. The most successful SaaS companies do the same.
2. Emotional selling: People don’t only buy features; they buy the story. Diamonds became a story about love, status, and commitment. What’s the deeper emotional pull of your SaaS?
3. Shaping perceived value: De Beers made diamonds feel scarce and irreplaceable. SaaS companies can do the same with exclusivity, premium positioning, and community-driven demand.

What’s your “Diamonds Are Forever” moment?

De Beers sold diamonds, but more than that, they crafted a vision that made a gemstone in declining demand become a lifelong symbol of love and commitment.

The best SaaS companies don’t just solve problems. They create movements. They change the way people think about what’s necessary.

What’s the standard your product could set?

Hit reply — I’d love to hear your thoughts.

—Corey