Behavioral economics & viral marketing case studies











Bandwagon Effect Details
Bandwagon Effect means we’re more likely to choose something when we see many others choosing it. Popularity acts like proof.
Think of hearing that everyone is watching a new show. Even if you weren’t interested before, you feel a pull to check it out, partly to fit in, partly to not feel left out.
In marketing this bias powers social proof, bestseller tags, reviews, waitlists, and visible community numbers. When people see a crowd, they assume the choice is safe and worth joining.
Bandwagon Effect Guide
Bandwagon EffectResearch
The study examined the bandwagon effect in luxury buying. It focused on how much people want a luxury product when they believe popular or high-status people already use it.
The researcher ran 3 experiments with 60 teenagers, 76 female students, and 73 male students/graduates.
When people saw a message saying “popular people use this product,” several things changed:
The study clearly showed that the bandwagon effect works: when a product is linked to an admired group, people want it more, pay more, and choose options that signal status.
Cialdini’s famous hotel-towel study showed that people follow the bandwagon effect.
Guests saw 3 messages:
Message #2 increased towel reuse by 26%, and the message #3 increased it by 33%, making it the most effective. The study proved that people follow what others do, especially when the group feels close or similar to them.
Bandwagon Effect Examples

1. Clubhouse
When Clubhouse launched, people rushed in not because they needed audio chats, but because thousands of others were already inside. The invite-only system made it feel like a growing party you didn’t want to miss. The Bandwagon Effect created explosive growth to 10M weekly users before the hype faded.

Game of Thrones became a cultural event partly because huge numbers of people were already talking about it - memes, spoilers, theories, and reactions filled the internet every week. Even people who normally don’t watch fantasy felt pressure to join in, just to understand conversations at work or avoid feeling left out. The Bandwagon Effect turned the show from a niche book adaptation into one of the biggest global TV phenomena, reaching over 19M viewers for the finale.

TBH grew insanely fast because its viral loop was engineered to spread inside one school at a time, not across a whole city or country. When the app launched in a new school, hundreds of students got the same notifications, polls, and compliments at once, creating the feeling that “everyone here is using it.”
This hyper-local explosion triggered a powerful Bandwagon Effect. Once a few classmates joined, the whole school rushed in, because no one wanted to be the only person not included.
TBH hit millions of downloads in weeks, not because the app was global, but because each school became its own viral ecosystem driven by social pressure and FOMO.
Scarcity Details
Scarcity means we value things more when they feel limited. When supply drops, desire rises, even if nothing else changes.
Think of seeing only a few items left on a shelf. Suddenly the product feels more important, even if you didn’t want it a minute ago. The fear of losing it boosts the urge to act.
In marketing scarcity turns hesitation into action. Limited spots, low stock, and short windows make people move faster because waiting feels risky.
Scarcity Guide
ScarcityResearch
A large meta-analysis of 131 studies and 416 effects found that not all scarcity works the same.
A group of 200 female students rated how attractive cookies were when there were many of them (abundant), when there were few (scarce), and when the amount changed. When cookies became scarce, the students were told it happened either because many people wanted them or because of an accident.
As a result, the cookies were rated more desirable when they were scarce than when they were abundant.
They were also rated more valuable when they changed from abundant to scarce compared to being scarce the whole time.
Scarcity caused by high demand got the highest ratings, while “accidental scarcity” scored lower. And cookies that stayed abundant the whole time were rated higher than cookies that started scarce and later became abundant.
Scarcity Examples

When Snap released Spectacles, you could only buy them from special vending machines called Snapbots. They appeared in random places without warning, so it felt like a surprise game of first come, first served.
This unpredictable availability created strong FOM and as a result, Spectacles became a cult gadget.

MSCHF releases strange products in small, surprise drops. You never know when the next drop comes, and they never restock, so people rush to buy. This makes every product feel rare, special, and worth grabbing fast.

TBH launched only in a few high schools and only in one state at the start, nobody else could download it. This created massive FOMO in nearby schools. Because of that (and many other brilliant aspects), the app was downloaded 5M times within 2 months.
FOMO Effect Details
FOMO is the fear of being left behind. It's your brain’s alarm for not missing out. It’s that quick fear that others are getting something good and you’re not.
It’s not logic, it’s old survival wiring. Long ago, missing what the tribe had could mean less food or safety. Today, it’s just seeing others win online and feeling behind.
Think of scrolling social media where everyone’s on trips, launching things, looking happy, and you suddenly feel the need to catch up. That’s your brain pushing you to act fast.
In marketing, FOMO works like fuel. Phrases like limited stock, last chance, or everyone’s already in trigger that fear and make people decide quicker.
Your brain’s fear center lights up when you think you’ll be left out, so you rush to join.
FOMO Effect Guide
FOMO EffectResearch
The online retailer tested a limited next-day shipping offer against another version in which the limited offer wasn’t shown.
The limited-time shipping offer boosted sales by 226%! All it took was one line of text with a countdown.
FOMO Effect Examples

1. The Dutch postal code lottery
To win the prize of the Dutch postal code lottery (the largest charity lottery in the Netherlands) person needs to buy a ticket and reside under the postal code drawn.
People who didn’t buy a ticket but could have won the lottery will be notified.

Booking.com has multiple examples of FOMO on every page. Booking.com is showing the visitors that they have actually missed out on a great deal.