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How To Boost Word-Of-Mouth Sales

Word of mouth marketing is an inexpensive way to increase sales and bolster brand loyalty. Referral sales growth can set one brand apart from the competition and get people excited about new product rollouts or redesigns.

But boosting WOM sales proves an elusive goal for many brands who just can’t seem to get the conversation rolling from authentic sources. We know that prospective users and customers are much more likely to trust advice and recommendations from their friends and family. How can companies earn those recommendations, though?

It takes more than just a high-quality product or a bargain price. Read on to find out everything managers and creatives need to know about word-of-mouth sales and learn a few tips to get people talking and boost WOM sales.

What Is Word Of Mouth Marketing?

WOMM, or word-of-mouth marketing, is what happens when fans of a product spread the word to friends, family, and other contacts. With the advent of social media, word-of-mouth marketing has become even more important because users and customers can interact with brands and display their testimonials to a huge audience in real-time. 

Word of mouth marketing has many channels. Anywhere people talk, they can make recommendations about the products and services they enjoy. And it’s certainly nothing new – testimonials are well-known promotional tools even if some modern research maintains that marketing-stimulated word of mouth is “often overlooked and rarely measured.”

Many companies have included socialization tools like reviews, comments, and shares on their sites and apps and tied referral fees into their model to encourage word-of-mouth marketing. To understand why these are sometimes effective and sometimes not, it’s helpful to understand the psychology of word-of-mouth marketing.

Social Proof Theory & WOM Marketing

There’s no doubt that humans are social animals nor that we’re heavily influenced by what the people around us are doing. Social proof is the theory that when we aren’t sure what to do, we look to other people as behavior models to imitate. It helps us get by when we’re in a new place with unfamiliar customs and it also helps explain why we have such a strong urge to confirm products are worthwhile with opinions and testimony from others.

Five friends hang out near a chain-link fence.
We’re most likely to take recommendations from close friends and family.

Normally, we have attributed some kind of authority to people if we accept their opinions as valid. In the case of online reviews, it used to be enough that the review was even posted. Over time, fake reviews were posted across the web, causing services to have to restrict comments and posts to people whose experience could be verified. 

For instance, many accommodation websites only send requests for review to people who completed a reservation and who are confirmed as guests by the host. Many eCommerce sites also have a feature for highlighting reviews from confirmed buyers. 

Social proof theory doesn’t only apply when we’re unfamiliar with the product, though. It seems whenever people are second-guessing or unsure about whether to (re)invest in a good or service, they again require some social proof to make a final decision.

And it’s not only through reviews and customer testimonials that we find the social proof we’re looking for. The presence of the good or service, social media shares, an expert stamp of approval, and celebrity endorsements all reinforce the social proof theory.

Which Social Proof Will Boost WOM Sales The Longest?

Research shows that referrals from word of mouth marketing “have substantially longer carryover effects” than traditional marketing techniques. So what kind of social proof will make the greatest impact and foster lasting brand loyalty?

Interesting products cause immediate discussion and referrals but more publicly visible products that are cued more often in a person’s environment are more likely to produce WOM immediately and over the long-term.

It’s not just that the product itself has to be earth-shattering or disruptive. The social proof needs to be there to get people talking about it and keep the brand on their mind so they use it as a resource when they need to.

There are a few main types of social proof that work to create buzz and WOM around products.

1. User Social Proof

Current users of a product or service are generally taken at their word when they recommend it. For this social proof to be most effective, it should be easy to see that these are authentic users, preferably ones who lead similar lives to our own.

2. Expert Social Proof

Professional experts like scientists, doctors, and athletes have an outsized impact on the way we perceive brands, products, and services. This is why you see commercials where licensed dentists approve toothpaste brands, veterinarians approve dog food, or pro athletes endorse fitness equipment.

3. Celebrity Social Proof

Unlike the first two categories of social proof, celebrity social proof is based on the desire to be like famous people or, in some cases, to have them be like us. This works particularly well for luxury brands that sell automobiles, watches, or wine. Everyday goods like credit cards have also had success with celebrity endorsements and spokespeople.

4. Certification

Some social media sites give users marks of approval such as a “verified” sticker or a checkmark. Brands that offer such certifications aim to be seen as a voice of authority and give especially active users something to show for their commitment. Miss the mark and give out certification that seems pointless or unwarranted, though, and the reverse effect is possible.

5. Wisdom of the Crowd

Just as individual endorsements, testimonials, and reviews have an impact on the people who read them, large numbers of engagement make a product or service seem more coveted and valuable. “One million users can’t be wrong” is a good example of a marketing slogan that might be used in a campaign aiming to tap into the Wisdom of the Crowd social proof.

6. Wisdom of Your Friends

Even more impactful than a bunch of strangers using a product is a majority of your close friends using it. In some ways, our social circles are tastemakers for us. Potentially some friends could be viewed as more fashionable or experienced than others, but in the end, most people will follow their friends’ lead when it comes to products and brands.

Keys To Referral Sales Growth

Now that we understand why word of mouth marketing works, let’s take a look at some strategies brands use to boost WOM sales and spur on referral sales growth.

The goal of WOMM is to not only get people talking but to get them to recommend a brand or product. To reach this goal, marketing creatives need to have a strong understanding of WOMM and what separates it from traditional advertising efforts.

Firstly, word of mouth marketing is not passive like radio, TV, film, or digital advertisements. Native ads might be preferred but they still don’t take any active effort from the viewer. The search for reviews or testimonials and testing the veracity of their claims is far more active and, for many consumers, a source of entertainment in its own right. 

Ok, maybe people aren’t so concerned with hunting down the truth behind a random product review on Amazon. But there are certainly large numbers of people on Twitter and other social media sites who are entertained by humorous reviews – even when they have nothing to do with the product and aren’t likely to know what it is, people are receptive to viewing these posts. 

When someone is searching for a product or service (or at least open to becoming a paying customer) then engagement is even higher. Not only are potential buyers checking around to get a sense of the aggregate feeling for a brand or product, but they likely “regard WOM as a much more reliable medium than traditional media.”

So when they can verify what others are saying in reviews and testimonials, people are more likely to become buyers themselves. The relationship between social proof and word-of-mouth marketing doesn’t end there, though. That high opinion of the brand can be sustained for long periods if the product is good, fairly ubiquitous, and the social proof that convinced people to buy in the first place doesn’t dissipate. 

Social media makes this ubiquity more possible than ever because comments, shares, and interactions between the brand and users on the site tend to reinforce social proof and keep people engaged with the brand even after they’ve made a purchase. In many cases, these social media interactions formed a significant part of the original social proof to begin with. 

If you want to attain referral sales growth, your first step is to retain buyers as repeat customers. This is why so many marketing professionals are obsessed with creating brand loyalty and WOM sales. 

Secondly, brands that want to increase referrals need to incentivize WOM and make it worth people’s time to refer their friends, family, and followers. In some cases, the best way to do this is to offer the product, service, or certain upgrade features for free. Other times, referral rewards are the best option. Occasionally, both strategies are employed simultaneously. 

For instance, many software as a service (SaaS) companies that offer premium subscription packages will let users have a month or more with these features unlocked if they refer a new user. The reason that approach works with SaaS is that many people will use the free version of the product without issue – the users who do pay are high-value customers. 

Other business models have customer bases that don’t mind paying for their product or service. In that case, giving away the product for free doesn’t make as much sense. Rather, giving rewards such as discounts, gift cards, or upgrades works better. 

Most apps have such referral programs in place. Food delivery, for example, might incentivize referrals with upgraded extras, waived delivery fees, or discounts for users who refer people to their service. Many companies also offer discounts on first orders for people who have just registered for their service.

People Will Talk – How to Create Buzz

When you have one of these referral programs, you need to back it up with strong advertising. Right?

As it turns out, advertising too much with traditional methods can deter your WOM campaign from taking off. Aniko Öry, an assistant professor of marketing at Yale’s SOM, puts it this way: “If I think you’ve already seen an advertisement, there’s no point in me telling you about a product. I’m more likely to talk about it if I think you’re not aware of it.”

To some extent, the research Öry is discussing reveals that it’s not only the activity of others that gives us the social proof we need to believe in the quality of products and brands. People will only go the extra mile and tell their friends about something if they believe it’s new knowledge. 

In other words, if you see a movie trailer everywhere, you start to presume that all your friends and family have already seen it. Even if you like the movie, it might not occur to you to bring it up. The same goes for the quality of the movie theater where you saw the movie.

Brands need to satisfy the needs of their customers in a way they can’t stop talking about. That process starts with identifying the right pain points from the earliest stages of product development. Try and solve problems that users aren’t consciously aware they have to deal with and they’ll be more likely to spread the word about the impact your product had on their lives.

What Brands Can Do To Boost WOM Sales

Beyond surprising people with the greatness of your product (which you should still be aiming to do anyway), brands need to keep up with trends to stay relevant enough to merit mention when their customers are talking with friends and family.

The number one trend to follow these days is the high demand for content, particularly user-created content. Companies in various industries have found out just how successful content-driven marketing can be. It gives people what they want – information – from sources they trust more than direct brand voices. 

This user-created content can include reviews and product testimonials or it could be centered on information related to the product or the brand’s expertise. If reviews aren’t a central part of the content, then the company should ensure that customers still have somewhere they can leave comments and reviews. If you don’t, a third-party site will, and in that case, there’s very little you can do to impact the impression of your brand. 

If you aren’t already connected with influencers and industry professionals, you’re behind. The brand doesn’t necessarily have to sponsor a young influencer on YouTube, but there should be some visible connection between your brand and professionals in your field. This demonstrates the quality of your brand and taps into that expert social proof we mentioned earlier in this guide. 

Sponsor meetings, public research, or forums. It might be a hard sell for managers and other stakeholders, but allocating part of the budget to sponsorships that allow everyday people to engage with subject matter they otherwise wouldn’t (under the auspices of the brand) can lead to significant ROI because of the positive emotional connection it creates. 

If there’s anything that defines the direction innovation is headed in our current moment, it’s the revelation that companies can advertise without advertising. They don’t have to constantly be engaged with mentioning their product lineup, brands, or how they stack up against the competition. Many people privilege lived experiences over everything else and they’re happy to form positive relationships with the brands that help facilitate good experiences. 

A smiling woman uses a pepper mill while cooking in a white kitchen.
From cooking tools to good schools, news travels fast when a product is good.


Word of mouth marketing is the key to referral sales growth and strong, long-lasting branding. It’s not always easy to create buzz around a product or service, but some marketing strategies will help. 

Online tools like social media and user review sites have made WOM marketing efforts easier but more commonplace at the same time. If you want your efforts to succeed, you need to surprise and delight users with what your product can do.

Use the tips and explanations in this guide to boost WOM sales and keep a positive emotional connection with customers. They’ll be more likely to return as repeat customers themselves and spread the word about your product to other people online or in person. 

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