According to wikipedia, the social proof phenomenon can be described as "a psychological and social phenomenon wherein people copy the actions of others in an attempt to undertake behavior in a given situation".
We humans, take lots of shortcuts in our thinking and decision-making process. Those are cognitive biases (An excellent book that goes in depth into those is "Thinking Fast and Slow").
Social proof describes the effect that instead of wasting hours researching each and every decision, we trust a lot the decisions of our peers.
A few concrete examples:
- You are much more likely to like a tweet already liked 209 times than one liked 0 time
- Checking reviews on Reddit before buying a product / signing up for a service
- Relying on ratings before downloading an app
- Buying something because a friend told you about it
It can be fun to try to recognise it when you make (small) decisions and see how it affects you. You'll be surprised!
Now, there's a lot of ways to use social proof to our advantage to improve sales or conversions.
- Adding testimonials to your website
- Increasing your social media presence
- Encouraging word of mouth, affiliate can be a good technique
- Making great products for great reviews
- Being transparent as to who (and how much people) are using your app