4 Viral Strategies That Grew Billion Dollar Companies

4 viral strategies that helped grow $1b companies

Airbnb. Dropbox. Slack. We call them unicorns, but the fact that these former startups with $1B+ valuations are becoming less and less rare means that there’s never been a better time than now to take a lesson from their playbooks.

Even better, you can use the same tools they did to build their customer bases and achieve rapid growth.

Back in the mid-2000s, big data, A/B split testing, and agile development cycles were ultra-sophisticated tools that only the earliest adopters used. Today though, strategies like these are commonplace enough that you only have to look online to find all the resources and tutorials you’ll need to drive your own company’s growth.

Below, we’ll walk you through how some of the biggest names in tech leveraged virality to grow to billion-dollar unicorn status. But since not all of us feel like the next Airbnb, we’ll show you how smaller companies have been able to use these same techniques to accelerate their success.

Get excited, and get inspired. All the tools and resources you need to build a billion-dollar brand are ready and waiting at your disposal. As a young company, you can take matters into your own hands and build a thriving customer base using the twin powers of referrals and virality.

Here’s how to do it.

4 Strategies for Achieving Virality

For lots of marketers like you and me, going viral means getting a piece of content, a social media post, or a story about us shared widely.

For unicorn companies, it often means something else: to drive serious business growth via referrals.

That makes sense – when you’re valued at billions of dollars, you’re unlikely to lie awake at night worrying about the virality a single piece of content might or might not achieve. Chances are you’re going to be much more concerned with how much people are talking (or not talking) about you as a whole.

Let’s take a look at how some unicorn companies have achieved that elusive status and what viral success really looks like.

1. Build Virality Into Your Product

Many of today’s biggest brands can attribute a huge part of their growth to virality. Not just a viral marketing campaign, but actually building virality into their product, so that with each additional customer they begin to see more and more growth.

By ‘building virality into a product’, I mean giving users an incentive to share, and making the product itself shareable on a grand scale. This usually means building enhancements into the product that users can gain access to by bringing other people on board.

Let’s see some examples.

Create a referral loop like Airbnb

A referral loop incentivizes customers to refer as many people as possible by offering a reward for each and every new customer that successfully signs up (via referral).

Let’s set aside the fact that Airbnb is a great idea executed really, really well. We know this played a huge part in getting the platform to where it is today, but finding and filling a gap doesn’t automatically equal success.

What helped make Airbnb one of the biggest and most-recognized brands in the world today was some very clever marketing. Specifically, the referral loop.

Airbnb supercharged the growth of its user base by implementing a referral loop designed to encourage new hosts, and new guests, to come on board.

Current guests and hosts are asked to refer their friends (to become guests, hosts, or both).

When a referred friend successfully completes their first booking, the referrer earns credit that can be used against their next booking. If you refer someone that becomes a host, you’ll get a (higher amount) in Airbnb credit when they host their first guest.

A smartphone with an example of Airbnb's popular referral program on it

(Image via Buyapowa)

This is a win-win for Airbnb (and its users). The scheme encourages users to refer as many people to the site as possible. Better yet (for Airbnb at least), the company only pays out when a referred user becomes a paying customer.

Create a double viral loop like LinkedIn

A double viral loop scheme helps drive engagement amongst a company’s existing customers, whilst also helping bring new customers on board. 

Most viral loop referral programs are based around new users only, and that’s not a bad thing. In fact, the concept has worked well for many companies, as we’ve just seen.

But some companies have adapted this technique in order to create what’s known as a double viral loop scheme. The idea is that it engages existing users alongside new users, and this particular technique played a big part in the growth of LinkedIn.

Four people sitting on a couch together using LinkedIn's referral program

(Image via LinkedIn)

Let’s see how it works.

When a new user registers with LinkedIn, they’re presented with the names and photos of lots of other users that LinkedIn believes the newbie might know. They are then asked to tag 10 of the users that they do know, and at the same time, send those people invitations to “connect.”

When an invite is accepted, the acceptee is shown a list of other people they might know. They tag the people they do know, and the cycle continues.

It’s worth noting that this case demonstrates how a viral loop can be used internally. The loop isn’t being used to bring more people to the platform, but to help current users connect with more contacts and get more out of the platform – something that’s integral to LinkedIn’s success.

Offer a great incentive for customers to share that doesn’t hurt your bottom line, like Dropbox

Many referral schemes leave the company in question out of pocket, however, depending on your product it might not have to.

When we talk about viral referral marketing, Dropbox usually comes up. That’s because most – if not all – Dropbox users will be familiar with the scheme. It enables users to get more out of the product without coughing up cash, so it’s understandably very popular.

The main page of Dropbox's user referral program

(Image via Dropbox)

The concept’s pretty simple. When you initially sign up for Dropbox, you get 2GB of storage space for free. When that runs out, you can pay for more storage. Alternatively, you can invite a friend and in return, you will both get an extra 500MB of space, for free.

Something for free vs. paying for it – that’s a no-brainer, right?

The fact that users can repeat this process up to 32 times is where the viral factor comes into play – imagine how fast Dropbox could grow if each user referred 32 friends, and all of those 32 referred another 32 friends?

Of course, that’s never actually going to happen. One of the downsides to Dropbox’s referral program is the fact that it’s relatively easy to abuse. If you have multiple email accounts (and who doesn’t?) or you feel like creating a new email account (hardly a huge task), it’s pretty easy to exploit the system and earn yourself extra space without providing anything to Dropbox in return.

That said, I don’t doubt Dropbox knows this happens, and accepts it as a necessary evil of running this sort of scheme. After all, it’s not like the company has to dip into its pockets to fulfill the rewards.

Make sharing really easy, like Harry’s

Incentives aside, you won’t get the results you want or need if you don’t make sharing as easy as possible.

Shaving brand Harry’s is a not-quite-billion-dollar company that grew out of a subscription service. Today it also boasts an e-commerce store and a barbershop in Manhattan’s West Village. It also owns the 90-something-year-old factory that produces its blades.

That’s seriously impressive for a company that celebrated its third birthday in March 2016.

So, how did they do it?

When launching a subscription service, you want to be confident that you’re going to be able to sign up enough subscribers quickly enough to sustain you throughout those initial make-or-break months.

To maximize its odds of getting the service off to a running start, Harry’s executed a week-long pre-launch referral program designed to collect the email addresses of as many potential qualified customers as possible.

By the end of that week, Harry’s had secured the email addresses of 85,000 potential customers.

Not bad, right?

Let’s find out more.

At the heart of this campaign was a two-page microsite.

Page one asked interested consumers to enter their email address.

Harry's popular referral program is shown on a tablet

(Image via Buyapowa)

Page two asked them to invite friends to learn more. If they invited enough people, who subsequently converted by signing up for updates themselves, the invitee would be thanked in the form of free products.

The referral page from Harry's refer-a-friend program

(Image via Harry’s)

To manage the scheme effectively, each email address entered generated a unique referral link. When a referral used that link to come to the site, the visit was saved as a cookie. This allowed Harry’s to track which referral visits added themselves to its email list, and who generated the referral.

Of course, there’s a direct cost to running a scheme like this. Unlike Dropbox’s referral scheme, it was critical for Harry’s to weed out any attempts at gaming the system (especially since, at this point, it was a brand-new startup).

As a result, Harry’s implemented a two-step process to prevent people from taking advantage of the giveaway:

  1. It used IP blocking. If a single IP address tried to sign up with more than two email addresses, that address was blocked from adding any further addresses to the campaign.
  2. It used SendGrid to identify and block fake email addresses.

Harry’s was also well aware that simply adding addresses to its list and notifying subscribers when the service went live was not enough to secure the startup’s success. To boost subscribers and increase its odds of leveraging this list effectively, Harry’s:

  1. Made subscribers feel privileged by crafting copy that made out like they were getting insider access to an exclusive club.
  2. Offered tangible rewards – items people could hold and use in real life – in place of virtual rewards.
  3. Ensured the rewards were achievable.
  4. Gamified the experience by making it easy for subscribers to view how many of the people they referred had also subscribed.
  5. Simplified the sharing process with pre-written messages that could be used on social media.

As the week-long campaign wrapped up, the results surpassed all expectations.

“Before the prelaunch, our small team set wagers on how many emails we would collect.

We wrote the figures on a whiteboard: Three thousand. Five. Seventy-five hundred. One bold person thought we could get 15k. We broke that high bar in the first day.” Four-Hour Work Week.

Make sharing fun, like Candy Crush

Building a little healthy competition into your product makes sharing it pretty much irresistible (and lots of fun).

Candy Crush needs no introduction. Even if you haven’t played it, you’ve seen the notifications from those that have, right? It’s one of the biggest viral app games of all time and is estimated to have made nearly $1.2 billion in revenue in 2020.

King – the game’s developers – did this in part by designing an addictive game, but more importantly, by building virality into it.

Users are encouraged to share their progress on Facebook so they can see how they measure up against their friends. This creates competition and that encourages retention. When users see their friends progressing in the game, they get the urge to return.

And the virality doesn’t stop there.

Whilst all that’s going on, the progress notifications keep introducing others to the game, too.

Key takeaway

Build virality into your product by finding a way or ways to make sharing your product irresistible, so that your current customers will be compelled to do your marketing for you.

2. Qualitative Testing: Live by Customer Feedback

Listening to customer feedback is always important, but for startups, that importance is magnified ten-fold.

Customer feedback can help you figure out whether you’re offering the right product to the right audience at the right price. If you can’t get those basics right, you’re going to struggle (a lot) to get your product to go viral.

Sure, sales data will give you a nudge in this direction. If no one’s buying, you know something’s wrong. Unfortunately, “something’s wrong” is the depth of the detail you’re going to get.

If you want to figure out what’s wrong – and you do – you need to collect and listen to customer feedback.

Slack is known for their commitment to listening to their customers and responding to feedback. The brand pays careful attention to their users’ comments and is quick to act on suggested changes and feature requests.

Want to implement something similar yourself? Here are some tools you can try.

Use social media and review sites

Customers with an axe to grind will often go public, rather than contact you in private. If that annoys you, I totally get it. Public complaints can feel like personal attacks, but instead of taking their comments to heart, treat them as snippets of advice you can use to improve your product, your service, and your business as a whole.

Bear in mind, however, that comments about your company won’t always be addressed to you, or posted to your social media channels.

To get around this, you can use a tool like Mention to track where your brand name is being used online.


There’s only so much knowledge to be gained by waiting for your customers to come to you. For best results, you need to be the one asking questions.

There are many ways to survey customers. You can:

  • Implement short surveys that pop up while people are browsing your site.
  • Send out post-purchase surveys (often preferable to the above depending on what you want to know).
  • Arrange one-on-one surveys with particular customers (over the phone if possible).

Customer service channels

This one should be obvious, but I (sadly) often find that traditional customer service channels are second-string behind public platforms.

Give private conversations the same attention as those that happen publicly. If anything, private communication channels offer a chance to have more meaningful conversations with customers since it’s all happening behind closed doors.

Key takeaway: 

Ask for, and listen to all your customer feedback. Be proactive and use surveys – don’t rely on your customers to tell you what you need to hear.

3. Quantitative Testing: Tracking Your Customers

The more you know about your customers, the more effective your attempts at leveraging virality are going to be.

Big data will play a significant part here. You’re going to want to collect data about your customers en-masse, and use it to create buyer personas that can guide your marketing efforts and help your company, not just your content, go viral.

The information you’re probably going to want to track may include (but isn’t limited to):

Demographic data

At a minimum, your customers’ age, gender, location, and interests. You should be able to collect some of this information as customers sign up and check out; however, most analytics platforms will help you delve a little deeper (and make it much easier to spot trends).

This information can help you build better viral campaigns that your customers are more likely to respond to and get excited about.

Transaction history

What products are people buying, and when? Which are your most popular products, and how do seasonal trends affect buying behavior?

If you want to incentivize customers with freebies it pays to know what they’re most interested in, and when.

This is what Appsumo did when they ran a competition designed to grow their email list: a competition that got them 200,000 new email addresses.

The landing page AppSumo's referral program

(Image via Appsumo)

To maximize the effectiveness of the competition they offered prizes that closely aligned with the interests of their audience. This meant that many of the resulting addresses belonged to genuine potential customers.

Of course, don’t forget about the part virality played in this. To be in with a chance of winning, entrants had to share the competition with their audience.

Social media

Where possible, “spy” on your customers’ social media activity to get a better understanding of what makes them tick. Watch what they say and what they respond to (as well as what they don’t respond to) and use your findings to guide future marketing campaigns and activities.

Track customer behavior

Every product has a “magic number” for adoption – even if the company behind it doesn’t know it. This can be the number of times a customer has to use the product or the number of “connections” they need to make before they become “hooked”.

It doesn’t even have to be a literal number. It could simply be an action or actions someone has to complete before they go from regular customer to loyal customer.

Whatever it is, once they pass that threshold, they’re far more likely to take an interest in the schemes that help your company go viral.

When Twitter launched, they noticed that the number of people users were following, and the number of people following them back played a key role in the odds a new user would stick around. Unsurprisingly, new users who didn’t follow anyone else were unlikely to come back.

As a result, Twitter quickly learned that if a new user followed between 5 and 10 other users right away, the chances of them returning and becoming loyal users increased significantly.

Slack has a magic number as well. Once a customer’s sent 2000 messages they are deemed to be safely on board and along for the ride.

Better yet, the benefits of knowing and understanding your new users don’t stop there. Once you know who your new users are, you can target viral campaigns or referrals straight at them.

Key takeaway:

Find out as much as you can about your customers – stalk them on social media if you have to – and use this information to create detailed customer personas that can help inform future marketing and content campaigns. Pay careful attention to how new customers behave, too. The quicker you find that “magic number” the sooner you can optimize your sign-up and onboarding processes to increase the number of customers that get “hooked” and stick around for the long haul.

4. Leverage Social Proof

Social proof plays a huge part in the decisions we make every day – far more than most of us realize.

We’re naturally inclined to pull together and behave as a pack. That’s nothing to be ashamed of – it’s just human nature at work. But as marketers, the knowledge that we are drawn to follow the actions of others is invaluable.  The interactions between our customers and prospects, our advocates, and our potential clients are part of a social recommendation engine that happens with or without our guidance.

Many of the concepts and cases you’ve seen in this article have been successful in large part because of social proof. Sure, something actually being good and worth sharing plays a big part in its ability to go viral – but not as big a part as social proof.


Because something going viral is social proof at work.

Let’s see some more examples of companies effectively leveraging social proof.

Piggyback off another platform, like Airbnb

If possible, identify a product or service that shares a similar audience to your own, and tap into it.

During its initial stages of growth, the Airbnb team faced a pretty significant problem: So long as hosts and guests were joining their site at a 1:1 ratio (or thereabouts) it would be really difficult (if not impossible) for hosts to successfully fill bookings.

To get around this, Airbnb leveraged another platform being used for a similar purpose – Craigslist.

The idea was very simple: it encouraged hosts to repost their listings on Craigslist.

Despite the simplicity of the idea, its impact was huge.

The strategy allowed Airbnb to tap into a market that was, at the time, far bigger than its own; a market that was formed in large part by the target customer (people after more “authentic” travel and accommodation experiences).

Airbnb also benefited from carefully-crafted listings that stood out among the competition on Craigslist. In general, Airbnb listings were more personal, had better descriptions, and had higher-quality photos, which significantly increases the odds of a property being booked.

And get users to share their experiences

Leverage social proof by providing a platform for your customers to share their stories.

A huge part of Airbnb’s success lies in how they found and filled a gap in the market – a need for more “authentic” experiences when traveling, experiences that could rarely be offered by the average hotel.

It made sense, then, that a culture of shared stories and experiences would feed into this, and that’s where social proof comes in.

While Airbnb’s a fantastic concept, people who are used to staying exclusively in hotels may find the idea of renting out a stranger’s home (whether a room or the whole place) a little unnerving.

The same goes for homeowners thinking about renting out a room for the first time.

Airbnb stories speak to their commitment to building and serving their community; the blog helps potential hosts and guests overcome these reservations by providing social proof that people not so different from themselves are staying in strangers’ homes or welcoming strangers into their own homes, and loving it.

Focus on making your product cool, like Slack

Going viral will be tough if there’s not a product on offer that consumers actually want to use. That’s why it pays to focus, first and foremost, on making something really awesome.

When it was starting out one of Slack’s key focuses was on making a product that was “cool” – something they undeniably achieved, along with collaboration software as a whole. Prior to the platform’s exponential growth, the concept of communicating using a private, social-media-type tool was widely shunned.

Slack changed this by designing a tool that was not only incredibly useful but also loads of fun to use.

“Most apps don’t bring me joy. Slack does. It’s so much more than just a messaging app. The attention to detail, the playful vibe, and the robust feature set all amount to an unparalleled user experience.” Theo Miller, Sitepoint.

This alone was enough to kickstart the viral social proof effect – something that has been integral to Slack’s success.

In fact, during Slack’s early development and growth, Slack had no salespeople. Instead, 97% of new customers were coming from referrals.

Another company who managed to make their product cool is Blueleaf, a financial tracking tool. It achieved something pretty massive: signing up 10,000 users before it had even launched.

Its business model has changed today, but when it was initially growing, one of its key USPs was that it was really hard to become a customer.

Yes, you read that right.

Blueleaf intentionally made potential customers work to get in.

In order to get access to the product, customers had to receive an invite either from Blueleaf itself, or a current customer.

But that wasn’t all.

Blueleaf would only let a limited number of new users in each week, and it chose who the lucky few were based on how much they appeared to want in.

Naturally, helping to spread excitement about the company would earn you big brownie points.

Key takeaway:

With all of the social platforms and review sites of today, social proof is more important than ever. Build trust amongst potential customers by encouraging your current users to share their experiences.

Why this all works (and what to do next)

A viral referral program offers a fast and cost-effective means of growing a company. In many cases, it’s much more effective than techniques like direct sales and advertising.


Because of social proof.

We’re naturally inclined to mimic what others are doing – especially when those “others” are people we trust.

This means a referral from a friend or family member tends to hold a lot more weight than that of an anonymous salesperson.

We know this works but bear in mind that it works best when you and your product are ready.

When you know you’ve got an awesome product that’s in a position to be scaled, launching a referral program with virality built-in is a seriously great way to do it.

Dream big, and when your product’s right, go for it. As we’ve seen above, it’s not just unicorn companies that can make schemes like this work – smaller companies are thriving off the back of viral referral schemes too.

Just be sure to come back and let us know how it goes.