Summary and Analysis of Contagious: Why Things Catch On

It is often argued that Rebecca Black’s song “Friday” went viral because it was so hilariously bad that people had to share it. It has since gotten millions of views that spike—you guessed it—on Fridays

NASA’s Pathfinder mission to Mars dramatically increased sales of Mars bars. This top news story made people think of the candy bar, increasing sales.
Jonah Berger’s book Invisible

According to the author, the average American discusses a brand or service 16 times per day.
Restricting the amount of an item that can be sold using a quantity purchase limit can increase sales over 50%.
According to Berger, word of mouth advertising is 10 times more effective than traditional advertising

Even though the Internet is seen as the medium for content and brands to go viral, word of mouth marketing is extremely important—much of marketing is due to real life contact. We all hang out with our friends and family, and what they say really matters. You’re much more likely to try a new food if it is recommended to you by your wife than by someone in an advertisement

Research by the Keller Fay Group finds that only 7 percent of word of mouth happens online.”

When creating a sale, something called the Rule of 100 is valuable in determining whether you should market it as a percentage (20% off) or in dollar terms ($5 off). The Rule of 100 states that for any purchase above $100, you should express the discount in terms of the dollar value. For example, advertising 10% off a $2,000 laptop doesn’t sound so great, but advertising $200 off the same laptop sounds quite a bit better, even though the discount is exactly the same

Occasionally, creating a campaign based on public awareness can go in the wrong direction. The famous Just Say No campaign against drugs spectacularly backfired because the ads made it appear that drug use was more prevalent than it really was. Even worse, the ads warned that the cool kids were doing drugs. This made kids who hadn’t been exposed to drugs aware of them, and it also primed them to think drugs were cool. Ironically, even though this campaign was intended to eliminate drug use, it led to an increase instead, all because it made drug use more visible

the fact that it has been rejected by others is a powerful motivator for you to also reject it in the hopes of getting a better one

Take kidneys. Around 40,000 Americans per year have kidney failure. 100,000 are on a transplant waiting list. Yet 97.1% of kidney offers are refused. How can this be possible? Many of the refusals are due to poor matching, but there are other reasons why kidneys are rejected. In fact, social proof is a key reason. If you are not at the top of the list, but you are offered a kidney, you know that many people have already rejected it. Even though you don’t know the reasons why

humans use social cues to make decisions. We like to follow popular decisions, to fit in, but also because we often trust the expertise of the group more than we trust ourselves