UX Virality Week: 2 of 7

If you want something to be really contagious, ideally it should jump from person to person as fast as possible. In product design, the time it takes to download something and “infect” the next person is called:

Viral Cycle


(Did you miss the first lesson? Start here.)

If you have seen the movie World War Z, you probably remember the scene near the beginning when Brad Pitt first watches someone get bitten and change from normal terrified person, into mindless, pissed-off zombie.

As señor Pitt counts to 10, the person goes through a full transformation, and he is afraid, because he realizes what that means.

It has a short viral cycle.

The scene is specifically meant to illustrate one of the fundamental principles of viral design: the faster it takes effect, the faster it spreads.


Make the user understand. Quickly.

When someone first visits your site, or downloads your app, or opens your software, they often to need to set it up, or register, or get a taste of the content, or learn what the buttons do, or play the first level… so they understand the value of it.

This is why “onboarding” — designing the first experience — is such a big focus for startups.

This is why an iPhone has a partially-charged battery when you take it out of the box.

So you get to the good stuff faster.


Time is money.

Your first reaction might be to think: “why spend all that effort creating something that doesn’t make the app better and doesn’t make any money? If your product is easy, people will figure it out.”

Technically, that’s not untrue. If the product itself is good, the user won’t necessarily get more out of it by getting started faster — other than a bit less annoyance.

But we’re not talking about a user. We’re talking about a virus.

Imagine two apps. One app that takes 10 minutes to get started, and one that takes 60 minutes. Fairly realistic. Otherwise, assume they are both amazing apps.

Viruses spread by multiplying exponentially. They infect one person, who infects 2 more, who infects 2 more, and so on.

That means that the 10-minute app can infect 32 people in the first 60 minutes, while the other app can only infect one person.

If we’re talking about zombies, a 10-minute viral cycle is scary. The 60-minute viral cycle is one zombie, locked in a room. 


So when designing something viral, the time it takes to get started and share it with the next person is called the Viral Cycle. And the shorter the better. Small differences for each user can add up to huge differences as it spreads across a network of people.


Tomorrow we will learn about the way a virus is spread from one person to the next, and how that can effect the contagiousness: Transmission & K-Factor.