I have always thought that using Social Proof as a reason to do things was a weakness. You were being a lemming, and we know what happened to the lemming don't we. Well then. Don't do that!
But I was told a rather nice story by Kyle Hughes. Back on the plains of Africa, imagine if a bunch of people you had never met came suddenly running over a hill toward you, shouting the caveman-ese for "Run Lions / Sabre-Toothed Cat!"
There are those, like me, who would say: "I have no reason to trust these people. I will stand my ground". But they were swiftly removed from the gene pool. And thus we take Social Proof rather seriously.
On a more mundane level you may have noticed that lots of people on LinkedIn have photos of themselves on stage, or speaking in some public forum. This is not because they spend most of their time on stage - far from it. It is because by suggesting that other people listen to them, so should you.
Social proof – People will do things that they see other people are doing. For example, in one experiment, one or more confederates would look up into the sky; bystanders would then look up into the sky to see what they were seeing. At one point this experiment aborted, as so many people were looking up that they stopped traffic.