A lot of things go into a person’s decision to purchase a product, and social proof is certainly one of those important factors. Studies show that 70% of consumers say they look at product reviews before making a purchase, and product reviews are 12x more trusted than product descriptions from manufacturers.

Product reviews are just one example of social proof. However, these statistics do give us insight into the value of social proof when it comes to marketing.

What is social proof?

Social proof is the concept that people will conform to the actions of others under the assumption that those actions are reflective of the correct behavior.

Thanks to social media, social proof has gained steam over the past couple of years, but in truth it’s been around for a while in marketing.

Here are some examples:

  • Night clubs and bars limit entry and make patrons wait in line outside. The visual of others waiting to get in increases the perception of the venue’s popularity. It is meant to entice a passerby to check out the club.

  • The way you sign up for most country clubs? You apply to a waitlist. The cost of joining aside, this furthers the perception that membership is an exclusive privilege.
  • McDonald’s restaurants include the line “Billions and Billions Served” on their signs.

  • TV shows play canned laughter or recorded applause to elevate the comical perceptions of situations in the plot. They want you to laugh along with them.

Although the concept of social proof may be nothing new, social media, user-generated content, and the internet have made it a lot easier to use it in marketing.

5 examples of social proof

To get you thinking about why social proof is important for your marketing and give you ideas on how to incorporate it, here are five examples of social proof, the science-proven reasons why they work, and an example of each in the wild.

5 Types of Social Proof

1. Expert social proof

Expert social proof is when your product gets a stamp of approval from a credible expert, like an industry blogger. This can come in the form of a Twitter mention, a press quote, or even a blog post.

The Science:

It’s a common practice amongst marketers to try and get “influencers” to endorse a product. But “influencer marketing” is more than a trend or buzzword; there’s science to back this practice up.

The halo effect is a cognitive bias in which we judge someone’s opinion based on our overall impression of him or her.

Influencers are well-known, so they already have established reputations. If it’s a positive reputation, anything else they are involved with is seen more positively by association. This is why influencer testimonials work.

Here’s an example:

Visitors referred by a fashion magazine or blogger to designer fashion rentals online at Rent the Runway drive a 200% higher conversion rate than visitors driven by paid search.


It makes sense, given that bloggers are becoming celebrities in their own rights. Which leads us to our next example…

2. Celebrity Social Proof

This is celebrity approval of your product or endorsements from celebrities. Celebrity endorsement is always a double-edged sword. If the celebrity is properly matched to the brand, it can do wonders for the company. If it’s a mismatch, it may produce a bad image of the company and its brand.

The Science:

To understand why celebrity endorsements work from a psychological perspective, it’s important to familiarize yourself with the concept of the extended self. The extended self is made of up the self (me) and possessions (mine). It suggests that intentionally or unintentionally we view our possessions as a reflection of ourselves. This is why consumers look for products that signify group membership and mark their position in society.

Here’s an example: was one of the first web startups to use a celebrity endorser back in 1997. William Shatner is not a travel expert or travel industry influencer, but he has an overall likeable image. It seems genuine when he tries to save consumers money.

The partnership has been a huge success for Priceline, which now has a $60 billion market cap. The fee that Shatner took in shares is estimated to be worth more than $600 million.

3. User Social Proof

User social proof is approval from current users of a product or service. This includes customer testimonials, case studies, and online reviews.

The Science:

User social proof is particularly effective when it involves storytelling.

We tend to imagine ourselves in other people’s shoes when we read or hear a story. This is why stories are so persuasive and often more trustworthy than statistics or general trends. Individual examples stick with us because we can relate to them. Although statistics can be effective, it can be tougher to really see yourself in the aggregate the way you can with a personal account.

Here’s an example:

Like many companies, Crate and Barrel invites customers to write reviews on the products they purchased. In addition to being able to rate the product on a five star scale, customers can also share photos of what the product looks like in person. The visual element to these reviews is particularly helpful and convincing.



4. ‘Wisdom of the Crowds’ Social Proof

This type of social proof is approval from large groups of other people. It’s showing evidence that thousands, millions, or even billions have taken the action that the company wants you to take – making a purchase, subscribing, etc.

The Science:

We kind of joke about FOMO in pop culture, but actually the Fear of Missing Out is a real thing. It’s a form of social anxiety, and it’s a compulsive concern that one might miss out on an opportunity. This anxiety is especially relevant for social media, as the sharing of what’s going on in our daily lives means you can constantly compare your status to others on these platforms.

Here’s an example:

On his blog Convince and Convert, Jay Baer drives email subscribers with a call to action that notes you’ll be joining more than 20,000 of your peers when you sign up for his newsletter.

The noting of the number of subscribers is a smart nudge, as it reminds potential subscribers that they don’t want to miss out on the valuable tips that their peers are already receiving.

Another common application of this form of social proof are “gated” sites. Frank and Oak and One Kings Lane both require signup before you can shop. This gives the impression that the experience is so popular, one has to be put on a waitlist.

 5. ‘Wisdom of Your Friends’ Social Proof

Social media has sparked dozens of different ways to provide this kind of social proof. Facebook widgets that show other Facebook friends that “like” a brand, Twitter’s display of people you follow that also follow another person, and the various ways that company offer rewards for referring others to the brand are all examples of this.

It’s a powerful marketing tool. One study of 10,000 accounts at a German bank revealed that customers who came from customer referrals had 16% higher lifetime value than those who came from other acquisition sources. Additionally, the customers churned 18% less.

The Science:

The concept of implicit egotism is that most people subconsciously like things that “resemble” them in some way. Studies show that we value the opinions of people we perceive as most like us. We tend to become friends with people that we have a lot in common with, so it makes sense that social triggers like Facebook’s Like Box or referral programs are successful.

Here’s an example:

Flash sale fashion retailer Rue La La offers an incentive to get customers to refer their friends to the site. When referred customers make their first purchases, the customers who referred them get $10 off their next purchase.


Put it into practice

Now that you are familiar with the different kinds of social proof and why they are effective, dive in and use them in your marketing.

A few quick ways you can use social proof right away:

  • Add customer testimonials to your website or newsletters

  • Emphasize your follower and subscriber numbers on your blog

  • Automate follow-up with great customers or contacts to ask for referrals

  • Find experts who are interested in what you’re doing, build relationships and work together to find ways that they can help promote you

Now, over to you – How do you use social proof in your marketing? Let us know in the comments.

P.S. If you liked this post, you might also like The Science of Social Media Influence: 10 Psychology Lessons to Make Your Posts More Persuasive and Why We Buy Into Ideas: How to Convince Others of Our Thoughts.

Image credit: marfis75

Looking for a better way to share on social media?

Schedule, publish & analyze your posts across the top social networks, all in one place.

Start a 14-Day Free Trial
Written by Ed Hallen

Ed Hallen is the co-founder of Klaviyo. is the eCommerce email marketing platform that helps stores grow sales by using data to send better, more personalized email. You can follow Klaviyo on Twitter or get more email marketing tips on the Klaviyo blog.

  • “We view a behavior as more correct in a given situation to the degree we see others performing it.” Cialdini

    So, if we cannot see ourselves performing a certain action, social proof is unavailable to influence us.

    • Jing Lam

      Right there!

  • I have noticed that I’m more likely to subscribe to a blog if it shows the number of people already subscribed… I guess I wonder what I’m missing out on if I don’t.

    • Same with me, Katya! If the number is over 1,000, I’m usually hooked. 🙂

      • ssstofff

        So, when starts faking, where it is less visible (the fake) than eg buying likes or followers ?

    • Sarah Flagg

      Agree, Katya! If I see a blog that’s been around for years and only has 100 followers, I take that as a huge reg flag.

      • DT

        What if it’s for a niche audience?

    • Fernando

      Yeah so true: the principle which can explain your feeling is even called that way: fear of missing out!

  • I’ve often said that it’s not the seller who sells, but the buyer who buys. We tend to want something, then look for a reason to justify/confirm it.

    • Love this perspective, Nathan!

  • Monica

    Customer testimonials works wonder for any website. Along with that, if you put some case studies, that’s like an icing on the cake !

  • Allie

    You provided a great insight into how brands are promoting their products through social proofs. Really intelligent course of action and it pays ultimately.

  • The SocialTimes article entitled “how to manage your social presence” included a nice [infographic] to help visualize the point that one of the first things you should do is to Google yourself and see what the search engines come back with. The author was making a point that we spend big $$ on our educated and advanced degrees but we shoot ourselves in the foot by having less than optimal social profiles out on the Net.

    From a “social proof” stand point, your tip to showcase your social followers and subscribers is spot on. If your USP (unique selling proposition) is about Video SEO but you only have 50 subscribers to your YouTube channel, your social proof won’t be so impressive to the reader. It’s very easy for someone to “socially vet” another person or brand in a few minutes, so its good practice to make sure your top social profiles compliment and confirm that your social credentials support your social proof.

  • Awesome read, Ed!

  • funkatopia

    I find it very funny that just as I was reading the “Wisdom of the Crowds” section, your pop-up appeared in the corner touting
    Join 19,638 other awesome people who get new posts by email!”

    • ssstofff

      I’m getting this popup too, with exact the same number ‘19638’, and this 25 days after your message … which makes it much less credible. Only for me maybe. Can’t be that rocket signs to put a live number.

  • Assaf Haski

    Great read and wonderful examples Ed!
    I think another good example is the Travel industry where today you can choose your flight and seat based on the people that will actually be on plane or choose an hotel based on the people who’s been there before.

  • Kathy

    perhaps you should add a link to the peace love & oats blog…

  • Even moral absolutists are consumer relativists. Social proof is certainly a valuable tool. Right now I’m looking for a way to make a page that shows my total number of social followers aggregated from all of the social networks I want to count.

  • A lot of our sellers include previous testimonials right on their product sales page. Reading a quote from a previous customer of the product you want to buy can be the last push a potential customer needs to click on ‘Buy’. Social proof is crucial, especially for those of us selling products online: there’s not a way to ‘test it out’ first. In cases like this, free shipping / returns and money back guarantees are helpful, too.

    PS. The link in the first paragraph with ‘70% of consumers’ in it is broken. 🙂

  • Natasja

    Interesting post! I want to share a new insight with you about social proof. It seems that social proof stated as ‘liking’ rather than ‘actions’ works better! So when you say ‘others bought this product’ it works, but when you use ‘people liked this product’ it is more persuasive and works better. It has something to do with people want to maintain the balance between conforming and uniqueness.

  • Great overview Ed, I’m gonna use it as a reference tool when needed :). Maybe you can add a little about social proof (Wisdom of the Crowd) in the sense of what they’ve bought versus what they’ve liked. Apparently sometimes people are more influenced by what other people want in stead of what they already have. Cool distinction, don’t you think? It’s recently discovered, more details are in this article:

  • Social Proof is one of the best ways to help you sell more of your products. If the quality and value is there, your clients will be your biggest salespeople. Nice post Ed!

  • Fernando

    Hi Ed,

    loved reading your article. Great tips! I am a marketeer myself and
    enjoy learning more and more about the use of psychology in marketing.
    I just read another article about social proof. there they explained how to
    use social proof specifically for new products. You can find it here, if interested.

    Might be a nice addition to this knowledge, if you did not know already

    Thanks again

  • That was an intense post. So essentially we need to integrate any form of social proof, but the forms themselves don’t differ that much?

  • These Social Proofs are not helping Much to get over something.