Social Proof: The wisdom of crowds

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Today, I bought Chris Brogan’s book, Trust Agents from Amazon. I’ve heard a lot about it over the past few weeks, mainly from the people I follow on Twitter. So, I went to, read the reviews and then placed my order.

And on the way I encountered at least 15 examples of Social Proof.

You may not be familiar with the term, Social Proof, but you’ll be aware of the concept. It’s the wisdom of crowds. The social phenomena whereby in times of doubt, us human will look to the crowd to aid our decision making. I‘m not sure, but all of them are doing it so that must be the right thing to do.

That’s not necessarily a bad thing. It can certainly help with making the right choice. If 10 of your like-minded friends all loved watching the film Funny People, then it could save you the ordeal of sitting through 81 painful minutes of The Final Destination.

There are times when it’s not such a good thing, such as with suicides. According to Brian Clark over at, “after a suicide is publicized, deaths by single-car accidents spike. When a murder/suicide is heavily reported, head-on car collisions and airplane crashes go up immediately afterward.”

The original suicide doesn’t cause the subsequent deaths, but likely provides an acceptance for those others that already want to kill themselves they can go through with it too.

(It’s a great social proof article by Brian, I recommend the read)

Away from the morbid stuff, let’s get back to Trust Agents and social proof.

The first example of social proof is the tweet. I follow a number of people on Twitter who I would consider experts in the field of digital marketing. These people cover topics as diverse as social media, search marketing, copywriting and product innovation. When they have something to say, I listen. The fact that they have tens of thousands of followers suggests I’m not alone (again more Social Proof).

The other Social Proof examples I experienced occur on Amazon.

Amazon gets social proof in a big way. It’s everywhere on the site. They do it so well, they have spawned thousands of copycat features all over the internet.

On the Trust Agents product page alone, I counted 14 instances of social proof – all whispering ‘Buy me, buy me’ in a very subtle, but persistent manner.

The most powerful ones for me are:

1. The star ratings – used twice on the page, at the top next to the title and the price and further down with the user reviews, the stars provide a simple but very effective means to evaluate the product at a glance. We trust what our peers say. We haven’t seen the book, so we can’t tell if it’s any good. They have and I believe them more than the blurb written by the publisher.


5 star ratings sell books

2. ‘What do customers ultimately buy after viewing this item?’ – not a snappy title, but a very persuasive feature. In the case of Trust Agents, 90% of those that viewed the page bought the book. Wow, it must be good. Almost everyone bought it. Perhaps I should be buying it right now too?

Evidence of peer purchases encourages further sales

Evidence of peer purchases encourages sales

3. Customer Reviews – potentially the most powerful of all the social proof examples. The written (or on some sites, video) review by a peer can contribute significantly to the purchasing decision-making process of the buyer. It builds upon the simplicity of the star rating, by providing depth and colour.


Customer reviews provide depth and colour

The stars tell me something is good (or bad) but the review tells me why.

If I’m buying a high price product, such as a camera, I want to know a little more about the pros and cons of the features. It can be surprising how the little things on a product can make or break your purchase of it. So being made aware beforehand that your potential new compact camera is an awkward shape that doesn’t easily fit in your pocket, can have a significant impact on your shopping basket.

4. I was going to leave it at 3 examples, but I couldn’t resist this one. Most products are not going to be so lucky, but fortunately Chris Brogan has admirers in influential circles. What better customer review could you have than one written by the highly respected Seth Godin?!


A positive review from Seth Godin is a Golden Ticket

So really, I had no chance. Once I hit that page I had no choice but to purchase. The power of social proof was too strong. Still, I got a pretty good book out of it.

What other examples of social proof have you seen? How persuasive were they? I’ll be writing a follow up article soon on how you can use social proof to improve your conversion rates. Please feel to share any examples you may have.

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Gary Robinson is a UK digital marketer, who fell into this tech world by accident and decided to stay and play. That was 1999. He's still here. His current loves are conversion optimisation, mobile and tinkering with new technology. He also has a fondness for coffee.

Posted in Business Performance


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