The Public Relations BlogDigital PRData-Driven PRHow To Build a Viral Loop (Using Mathematics)

How To Build a Viral Loop (Using Mathematics)

It's satisfying to build viral loops, but it's also hard as hell.

Cover photo: @jerrysilfwer


Knowing how to engin­eer a vir­al loop is a PR superpower.

In this art­icle, I’ll run the num­bers of a vir­al loop to help you con­struct your traffic-gen­er­at­ing machines.

As a digit­al strategist, I’ve designed many vir­al loops to gain trac­tion and gen­er­ate leads for B2C and B2B brands. Viral loops are power­ful, but they also break easily.

Here we go:

How To Determine Virality

Let’s say you post a hil­ari­ous cat video on YouTube. 

You share your cat video across social media and get your first 1,000 views. Out of those 1,000 view­ers, 10% (100 people) decide to share your cat video with their friends — once on aver­age. Each such share gen­er­ates 11 new video views, a total of 1,100.

Going from 1,000 views (1st cycle) to 1,100 unique views (2nd cycle) equals a vir­al coef­fi­cient of 1,1.

And any­thing above 1,0 = vir­al, woohoo!

How many views will you get in the 3rd cycle? Out of the 1,100 people in the 2nd cycle, 10% will share it once, gen­er­at­ing on aver­age 11 new views per share and — boom! — you get 1,210 (1,100 x vir­al coef­fi­cient) addi­tion­al views after the 3rd cycle.

Look at your cat video now, oh mighty Viral Loop Designer!

But before we get ahead of ourselves, let’s exam­ine the inner work­ings of a vir­al loop.

Viral Loop Weaknesses

Why aren’t all spin doc­tors involved in design­ing vir­al loops? Well, as it turns out — it’s chal­len­ging to get vir­al loops to work. 

Here are some vari­ables to consider:

Population Size

We can only expect your con­tent to per­form as long as you reach your tar­get audi­ence. Cat videos have an extens­ive appeal across demo­graph­ics, so your pop­u­la­tion size will be enormous!

But most busi­nesses have very little to do with cats. 

For instance, if you’re a CRM SaaS com­pany, you’ll prob­ably struggle to reach crit­ic­al mass for your cycles.

Loop Instability

By cal­cu­lat­ing aver­ages with­in each cycle, you might find some­what stable inputs for click-through rates (CTR), con­ver­sion rates, social back traffic, etc. 

But in real­ity, these indic­at­ors are volat­ile, and they fluc­tu­ate immensely from cycle to cycle.

Getting your 2nd cycle to per­form above 1,0 (vir­al coef­fi­cient) is often a chal­lenge, and it gets more com­plic­ated with each cycle.

Engagement Distribution

A key factor is social back traffic from people shar­ing your content

This aver­age traffic num­ber can be deceiv­ing; most shares hardly res­ult in any back traffic. It’s often shar­ing that keeps the aver­age up.

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The Engagement Pyramid

The 1% rule of online engage­ment was mainly an urb­an legend on the inter­net. However, a peer-reviewed paper from 2014 con­firmed the 1% rule of thumb. 1Trevor van Mierlo. (2014). The 1% Rule in Four Digital Health Social Networks: An Observational Study. Journal of Medical Internet Research, 16(2), e33 – e33. … Continue read­ing

Active pub­lics dis­trib­ute them­selves in a way proven sci­en­tific­ally by soci­olo­gists — long before the inter­net and social media emerged. 

The Engagement Pyramid divides pub­lics into three dis­tinct groups:

  • Creators (1%)
  • Contributors (9%)
  • Lurkers (90%)

When study­ing inter­net for­ums spe­cific­ally, it’s not uncom­mon to find that 90% of users have nev­er pos­ted (lurk­ers), 9% are adding only to exist­ing top­ics and threads (con­trib­ut­ors), and 1% are act­ively start­ing new sub­jects and threads (cre­at­ors).

The Engagement Pyramid is some­times called the 1% rule or the 90−9−1 principle.

The 90−9−1 prin­ciple and Zipf’s Law both effect­ively clas­si­fy mem­bers in online sup­port groups, with the Zipf dis­tri­bu­tion account­ing for 98.6% of the vari­ance.”
Source: Internet Interventions 2Carron-Arthur, B., Cunningham, J., & Griffiths, K. (2014). Describing the dis­tri­bu­tion of engage­ment in an Internet sup­port group by post fre­quency: A com­par­is­on of the 90−9−1 Principle and … Continue read­ing

Learn more: The Engagement Pyramid (The 90−9−1 Principle)

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Creators and con­trib­ut­ors tend to inter­act more, so you’re likely to run out of shares much more quickly than social shares from lurkers.

Cycle Times

YouTube is very friendly to vir­al mechanics: 

You watch a short video, share it, and the next cycle kicks in — often in minutes. Actually, from a math­em­at­ic­al stand­point (see math­em­at­ic­al for­mula), cycle time truly mat­ters more than social back traffic averages!

If you need someone to review a 30-page white­pa­per on SlideShare before being ready to share the con­tent, you might be facing an aver­age cycle time of sev­er­al hours (or even days). 

Reducing vir­al loop cycle time has, by far, the most sig­ni­fic­ant effect on vir­al growth.

External Factors

Your cat video isn’t the only social object com­pet­ing for people’s atten­tion. It’s impossible to fully con­trol or anti­cip­ate what con­tent will com­pete for atten­tion at any giv­en time.

We’re deal­ing with chaos the­ory here: There are too many unknown vari­ables to find, under­stand, and com­pute, from the ana­tomy of com­plex net­works to the slight­est details affect­ing indi­vidu­al behaviour.

Content Quality

Producing con­tent that inspires the kind of math dis­cussed above is quite chal­len­ging. With unlim­ited mar­ket­ing budgets, you might be able to enrol a team of world-class cre­at­ives with an organ­iz­a­tion of pro­duc­tion pro­fes­sion­als to match. But there are no guarantees.

Hundreds of thou­sands of tal­en­ted (or lucky) people are launch­ing attempts at vir­al con­tent every day. Can you be sure to beat them all at a time of your choosing?

Still hungry for vir­al suc­cess? What we want is to apply the vir­al loop to business.

Viral Project Economics

We could go on to cre­ate a “cat video,” mean­ing a video that’s cute and funny to a large num­ber of people and thus aim for the same math as described above and, for the sake of argu­ment, reach 1,000,000 views on YouTube. 

If the total pro­duc­tion cost (includ­ing pro­mo­tion costs) is $250,000 and the com­pany’s aver­age profit mar­gin is $50 per unit sold, a 1,000,000-view video that con­verts new cus­tom­ers at 0,01% (not uncom­mon) will gen­er­ate $5,000. And that is not great for a $250,000 video.

Also, if the busi­ness can man­age 1,000,000 video views on YouTube, how can any­one be sure that every­one watch­ing is poten­tial cus­tom­ers — and noth­ing else? There are oth­er ways for a vir­al video to cre­ate value bey­ond dir­ect sales:

  • Brand value
  • Brand aware­ness
  • Audience growth
  • Employer brand­ing
  • Data har­vest­ing (audi­ence analytics)
  • Email list building

Still, “money in the bank” should always be an essen­tial con­sid­er­a­tion. And there’s always the chance that your vir­al mech­an­ics fail.

Boosting Your Viral Loop

We’ll need all the help we can get. Let’s explore a quick over­view of help­ful vir­al tools:

Seed traffic. The 1st wave of traffic you gen­er­ate, either by activ­at­ing your exist­ing audi­ence, through influ­en­cer out­reach, or advert­ising. (Must reach crit­ic­al mass for the vir­al effects to be giv­en a chance to come into effect.)

Landing page. A page designed spe­cific­ally to har­vest a spe­cif­ic intent. Typical for land­ing pages is that they only have one call-to-action (CTA).

Landing pages serves a single purpose.
Landing pages serve a single purpose.
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Types of Landing Pages

Landing page (LP) = a single-pur­pose web page stripped of stand­ard menus and side­bars with a single CTA (call-to-action) chosen to match the visitor’s demon­strated intent.

Here are a few examples of land­ing page types:

  • Lead cap­ture pages. These are designed to gath­er con­tact inform­a­tion from vis­it­ors, usu­ally in exchange for some­thing valu­able like an ebook, a webin­ar, or a free tri­al. They typ­ic­ally include a form and a brief descrip­tion of what the vis­it­or will get in return for their information.
  • Click-through pages. These pages are used primar­ily in e‑commerce and SaaS (Software as a Service) indus­tries. They provide detailed inform­a­tion about a product or offer and lead vis­it­ors to a shop­ping cart or checkout.
  • Sales pages. Focused on dir­ectly selling a product or ser­vice. They often include detailed descrip­tions, bene­fits, testi­mo­ni­als, and a strong call to action (CTA) to make a purchase.
  • Squeeze pages. A type of lead cap­ture page, squeeze pages are designed to extract inform­a­tion from vis­it­ors, usu­ally through a form. They often have min­im­al con­tent except for a pitch and a form.
  • Registration pages. These pages provide inform­a­tion about the event and include a regis­tra­tion form. They are designed to sign up vis­it­ors for an event or a webinar.
  • Thank you pages. After a vis­it­or takes action (like sign­ing up or mak­ing a pur­chase), these pages thank them and can also guide them towards the next steps, like down­load­ing a resource or check­ing related products.
  • Launch pages. These pages are used for new products or ser­vices and aim to build excite­ment and anti­cip­a­tion. They might include a count­down timer, teas­er inform­a­tion, and an option to sign up for updates.
  • Unsubscribe pages. Used when someone unsub­scribes from a ser­vice or email list. They often include options to recon­sider the decision or provide feedback.
  • Coming soon pages. Like launch pages, they are used before a web­site or product launch to build anti­cip­a­tion and gath­er early interest or email sign-ups.
  • 404 error pages. While not a typ­ic­al land­ing page, a well-designed 404 page can turn an error into an oppor­tun­ity, guid­ing lost vis­it­ors back to the main site or to spe­cif­ic actions.

The above examples are to name a few examples of land­ing pages. Only your ima­gin­a­tion will determ­ine what types of effi­cient land­ing pages you can develop!

Each land­ing page type serves a spe­cif­ic pur­pose in the cus­tom­er jour­ney, focus­ing on a single object­ive: increas­ing conversions.

Read also: Types of Landing Pages

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Lead mag­net. “Free” online con­tent encour­ages poten­tial cus­tom­ers to opt in. Efficient lead mag­nets tar­get urgent needs that can be relieved quickly. (Also known as “opt-in bribes.”)

Uptick page. If you can get a per­son to take action, you’ve “primed” them. So, instead of let­ting them go, you can refer them to an uptick page where you can make an addi­tion­al ask of them.

Uptick bonus. Lead mag­nets tailored expli­citly for spe­cif­ic con­tent types are often called “con­tent upgrades.”

Referral engine. Often com­bined with uptick pages, refer­ral engines encour­age users to share more than once, often using a gen­er­at­or for unique URL addresses.

If you’re look­ing for ready-made tools, LeadPages with tem­plates for high-con­vert­ing land­ing pages could be a place to start. If you’re look­ing for uptick pages with built-in refer­ral engines, check out UpViral.

Viral Loops Step-by-Step

Let’s build an ima­gin­ary vir­al loop for the Doctor Spin blog, shall we?

Step 1. The seed traffic (some Facebook ads tar­geted at a lookalike audi­ence based on exist­ing email sub­scribers) is dir­ec­ted to a land­ing page. If your brand already has crit­ic­al mass, that helps, too.

Step 2. The traffic is offered a “free” (in exchange for their email addresses) lead mag­net (a three-day video course that tar­gets an urgent pain point, like “How to Succeed with Content Marketing in B2B”). Three con­sec­ut­ive videos allow for three sep­ar­ate uptick pages.

Step 3. On the 1st uptick page, the con­ver­ted users get the first video and are incentiv­ized to share my land­ing page with an uptick bonus (“Free Templates for Creating High-Converting Blog Posts and Landing Pages for B2B”). In this example, the user will get the bonus by refer­ring at least three friends to the ini­tial land­ing page. A refer­ral engine, gen­er­at­ing unique URLs for each user, keeps track.

Step 4. On day two, I use their email addresses to remind all signups that the fol­low­ing video is live on the 2nd uptick page. Once there, they are reminded again to share the uptick bonus.

Step 5. On day three, I again reminded the signups via email that the final video is live on the 3rd uptick page. Once there, they are reminded to share the uptick bonus a third time.

For the sake of argu­ment, let’s say that I send 1,000 poten­tial cus­tom­ers to my lead page, con­vert­ing at 40%, in turn send­ing 400 people to the uptick pages, con­vert­ing at an aver­age of 20%. The most act­ive users like the videos and the uptick bonus (I hope!) enough to share them 1,5 times on aver­age at 10 new land­ing page vis­it­ors per share.

  • 1st cycle: 1,000 tar­geted vis­it­ors, 400 new subscribers.
  • 2nd cycle: 1,200 tar­geted vis­it­ors, 480 new subscribers.
  • 3rd cycle: 1,440 tar­geted vis­it­ors, 576 new subscribers.

And so on.

Non-Viral Loops Have Value, Too

No vir­al loop lasts forever, of course. But hope­fully, this the­or­et­ic­al exper­i­ment demon­strates the raw power of vir­al loops. Three uptick pages are presen­ted sequen­tially using a land­ing page, an email remind­er func­tion, a refer­ral engine with unique URLs, a lead mag­net, and an uptick bonus.

When deal­ing with small pop­u­la­tion sizes (often for niched products or ser­vices), you must make sure to sus­tain your vir­al loop.

My favour­ite vir­al loop is that of Instagram:

When you take a pic­ture, Instagram allows you to edit and apply vari­ous fil­ters. When you engage in this activ­ity, you become cre­at­ively more attached to the image — it becomes more than a pic­ture; it becomes some­thing you’ve cre­ated. Social net­works are vir­al spe­cial­ists. It’s in their DNA, their busi­ness, to activ­ate online users. Doing it your­self for your busi­ness can be daunting.

Even if you only man­age to estab­lish a vir­al coef­fi­cient of 0,5 (and only keep it for a few cycles), these con­ver­sions might still make a big dif­fer­ence to your ini­tial mar­ket­ing effort — remem­ber the seed traffic?

Using Facebook Ads to pay for 1,000 click-throughs and adding a “0,5 loop” will con­sid­er­ably increase your ROI for the ini­tial ad buy. There’s no “free traffic,” but this is close.

Example (“0,46” loop):

  • Seed traffic: 1,000 views
  • Lead page con­ver­sion: 32%
  • Uptick page traffic: 320
  • Uptick bonus con­ver­sion: 16%
  • No. of refer­rers: 51,2
  • Shares per refer­rer: 1,4
  • Total no. of shares: 71,68
  • Social back traffic per refer­ral: 6,5
  • 1st cycle traffic: 465,2 views (“free traffic”) 
  • Viral coef­fi­cient: 0,46

In real­ity, for your type of busi­ness, trans­form­ing an exist­ing “0,5 loop” into a “1,1 loop” might be near impossible (and expensive). 

However, adding “0,5 loops” here and there might be straight­for­ward and cost-effi­cient — while doub­ling your mar­ket­ing ROI. The vir­al effect isn’t a bin­ary phe­nomen­on. Instead of think­ing of a “0,5 loop” as a failed vir­al loop, you should think of it as an online mar­ket­ing amplifier.

Not bad for a funny cat video.

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Thanks for read­ing. Please sup­port my blog by shar­ing art­icles with oth­er com­mu­nic­a­tions and mar­ket­ing pro­fes­sion­als. You might also con­sider my PR ser­vices or speak­ing engage­ments.

PR Resource: Why We Share on Social Media

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Why We Share on Social Media

People want to be loved; fail­ing that admired; fail­ing that feared; fail­ing that hated and des­pised. They want to evoke some sort of sen­ti­ment. The soul shud­ders before obli­vi­on and seeks con­nec­tion at any price.”
— Hjalmar Söderberg (1869−1941), Swedish author

When we share on social media, we share for a reas­on. And that reas­on typ­ic­ally has some­thing to do with ourselves:

  • We share to make ourselves look smart.
  • We share to fit in and to stand out.
  • We share to express individuality.
  • We share to belong to our in-group.
  • We share to be loved.
  • We share to pro­voke reac­tions for attention.
  • We share to extract sympathy.
  • We share to make us feel bet­ter about ourselves.
  • We share to get ahead.
  • We share to grow an audience.
  • We share to com­pensate for our shortcomings.
  • We share to get the respect we need.

If you can get social media to work for you, great. But you should also be mind­ful not to let the pres­sure get the bet­ter of you.

A status update with no likes (or a clev­er tweet without retweets) becomes the equi­val­ent of a joke met with silence. It must be rethought and rewrit­ten. And so we don’t show our true selves online, but a mask designed to con­form to the opin­ions of those around us.”
— Neil Strauss, Wall Street Journal

Learn more: The Narcissistic Principle: Why We Share on Social Media

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1 Trevor van Mierlo. (2014). The 1% Rule in Four Digital Health Social Networks: An Observational Study. Journal of Medical Internet Research, 16(2), e33 – e33. https://​doi​.org/​1​0​.​2​1​9​6​/​j​m​i​r​.​2​966
2 Carron-Arthur, B., Cunningham, J., & Griffiths, K. (2014). Describing the dis­tri­bu­tion of engage­ment in an Internet sup­port group by post fre­quency: A com­par­is­on of the 90−9−1 Principle and Zipf’s Law. Internet Interventions, 1, 165 – 168. https://​doi​.org/​1​0​.​1​0​1​6​/​J​.​I​N​V​E​N​T​.​2​0​1​4​.​0​9​.​003
Jerry Silfwer
Jerry Silfwer
Jerry Silfwer, alias Doctor Spin, is an awarded senior adviser specialising in public relations and digital strategy. Currently CEO at Spin Factory and KIX Communication Index. Before that, he worked at Kaufmann, Whispr Group, Springtime PR, and Spotlight PR. Based in Stockholm, Sweden.

The Cover Photo

The cover photo isn't related to public relations obviously; it's just a photo of mine. Think of it as a 'decorative diversion', a subtle reminder that it's good to have hobbies outside work.

The cover photo has



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