Remember the video of the guy who stood at a busy intersection offering everyone free hugs? The Free Hugs campaign was started by Juan Mann on December 1, 2004, when he began giving out hugs in the Pitt Street Mall in central Sydney.

That little video not only notched up millions of YouTube views but also started a movement, known as the Free Hugs Campaign.

What exactly makes a simple, amateurish video like that go viral? And what are the qualities that define viral content – the holy grail for marketers who want to promote a brand or product on social media?

Although there are no guarantees for making your content go viral, I believe that, like the Free Hugs video, virality is created by a number of factors that work together to appeal to a large portion of humanity.