Contagious illustrates why certain ideas and products spread better than others by sharing compelling stories from the world of business, social campaigns, and media.

Ever wondered why some random YouTube videos or Instagram accounts go viral, regardless of their quality or how cliché they are?

The answer is because people share them. Even if a popular video seems random to us, it clearly has qualities that make others want to pass it on.

We assume that some concepts or products become more popular than others out of sheer luck.

One article gets a million shares on social media and another, although similar, sees only a handful.

That's just how the internet seems to work – at least if we don't look any deeper.

But what if there was somebody who tried to find out what separates contagious ideas from the ones that never make themselves known?

Jonah Berger has been doing exactly this for over 15 years now.

Much like in the book Hooked, Berger digs deep into the psychology behind consumer choices. His conclusions about why some ideas spread like a virus are the core of Contagious: Why Things Catch On.