Social Proof

​Read online​

---

"Window cleaning in progress"

I love this board because it remembers something most marketers forget.

Cialdini proved that we're persuaded by others.

In an Arizonan hotel room, he placed two messages on hotel doors designed to convince guests to reuse their towels.

“Help us save the environment” = 35% towel reuse.

“Most guests reuse their towels” = 44% towel reuse.

We're persuaded by others' actions.

So, if a neighbour pays for window cleaning, we'll consider doing the same. But marketers forget one important element: consumers don't like to feel forced.

Messages like "We're the most popular" and "We're number one" work, but they're not perfect. Guéguen showed that people are more likely to act if they feel autonomous, not forced.

K&C Window Cleaning's sign gets this right. It doesn't say:

❌ We're the most popular window cleaners in Houston.

It says:

✅ Window cleaning in progress.

And plenty of other companies do the same. They don't say they're popular; they prove it.

My favourite example comes from Sam Tatam's* wonderful book, Evolutionary Ideas.

At his favourite cafe, the owners don't say, "we're popular", they show it by sticking the loyalty cards of their customers on the wall.

They don't say it.

They show it.

And that makes it far more effective.

---

Like newsletters like Nudge? Check out The Hustle ↓

The Business Newsletter for People Who Hate Business Newsletters

The weird, fascinating stories behind businesses quietly taking over, including my favourite: how gas station pizza became a billion-dollar industry. Join The Hustle's 1.5M readers.

Subscribe Today

---

Cheers,

​Phill​

*RIP. Sam sadly passed away in August 2025. His book is absolutely brilliant, and I had great fun interviewing him on Nudge in 2022. I believe all sales of the book go to his wife and kids, so if you haven't already, pick up a copy.