By Andrew Lindsay

Consider the zombie. A shambling, diseased, undead monster craving brains and terrifying moviegoers, TV audiences, readers, gamers, and Internet users. It seems like no matter where you turn nowadays there’s a savage, rotting beast waiting there for you, all milky-eyed and groaning for human flesh.

Our culture is as obsessed with zombies as the undead is obsessed with consuming the living’s grey matter. In just the past two years there have been 18 different zombie movies, including such blockbusters as Warm Bodies and Evil Dead. About 17.3 million viewers tuned in on October 12 this year to see The Walking Dead’s season premiere. World War Z: an Oral History of the Zombie War by Max Brooks (the son of beloved comedian Mel Brooks, by the way) sold more than a million copies back in 2011 and spent four weeks on the New York Times best seller list. Sony has sold more than six million copies of its ground-breaking zombie game The Last of Us. Marvel Comics even came out with an entire comic series featuring zombified versions of its superheroic characters.

But why? What is it about these strange monsters that we’re so fascinated with? If we can figure out why it is that the undead are so attractive to people, could we then somehow apply it to online marketing?

Zombies are nothing new, either, so their sheer novelty doesn’t explain their popularity. Humans have told zombie stories for hundreds of years. Haitian folklore has Bokors -- voodoo priests -- summoning and controlling “zombi,” or the spirits of the undead. The Norse dreamed up the draugr, which were undead Vikings who ate and infected their very-much-still-alive brethren. Even The Epic of Gilgamesh features flesh-eating, undead creatures.

However, it was that devilish film director George Romero who brought the zombie into America’s pop-cultural consciousness with his 1968 film, Night of the Living Dead (although there were several other earlier movies that featured a form of zombie), and they’ve been terrifying millions of people in the U.S. ever since.

Yet, the zombies in Night of the Living Dead are slow, shuffling husks of their former, human selves. Yes, they were coming to get Barbara, but she could really just outrun them if need be. They don’t really pose much of a physical threat (until they do get you, that is, but we won’t go there), so why then is the concept of the living dead so terrifying?

Author Stephen King, whose talent for creeping us out (and keeping us up at night) has led to worldwide book sales of over 350 million copies, says there are three types of fear. There’s the Horror, which is the aforementioned sense of physical danger. There’s the Gross-Out, which is the repulsion from gore and violence. Then there’s Terror, which, as the Maestro explains, is “when you come home and notice everything you own had been taken away and replaced by an exact substitute.”

Modern zombies -- the ones feasting away on our TV screens -- embody all three kinds of scary. Though some might only be able to crawl or shuffle, others are able to run at great speeds. They’re grosser nowadays, too, thanks to the dedication of Hollywood makeup artists.

Lastly, and most importantly, they’re terrifying, because most modern tales create very realistic scenarios leading up to a zombie apocalypse. They’re stories that point out the cracks in what we thought were society’s invincible pillars.

This verisimilitude is, in fact, codified by the rules of the horror genre. According to Screenplay: Writing the Picture, “We, in our foolish, rationalistic pride, are to blame for unleashing the forces of chaos and terror, by overstepping moral boundaries. Transgression leads to retribution. In normal life, certain things are forbidden, defined by conventional morality and wisdom as taboo.”

The characters in horror movies using the “cabin in the woods” trope typically invoke the wrath of the antagonistic monster, often a psycho-slasher like Jason Vorhees, because they party it up. They’re often youthful and foolhardy, and their hubris leads to their downfall. In other words, it’s their own fault. Compare this to zombie stories, in which people just get sick. The world-as-we-know-it ends because of a pandemic, similar to the avian flu virus or the Ebola outbreak. This fact is so ingrained in the genre that narratives-of-the-undead like Zombieland, The Walking Dead, and Warm Bodies just skim over this fact.

This is the main reason why we’re so obsessed with zombies; they’re not just terrifying -- they’re thoroughly, utterly terrifying and potentially realistic. Audiences don’t have to suspend their beliefs very much when enjoying a zombie story.

Of course, this begs the question: How would touching upon my website’s visitors’ darkest, most primal fears increase my online presence?

Simple. It won’t, but that doesn’t mean there isn’t a lesson here.

A study by Jonah Berger from the University of Pennsylvania suggests that the more evocative a piece of content is, the more likely it’ll get shared, because sharing provides people with a sort of closure. It helps people’s emotional states level out and get back to normal. Once they share a piece of emotional content, whether it’s a touching video of a soldier’s reunion with his dog or an anger-inspiring essay, they can move on from it emotionally.

When people watch The Walking Dead, it works them up. They then have to go talk about it on Facebook or Twitter to get it out of their systems. Social media users who didn’t watch then see the posts, and through a series of user-generated brand exposures, these uninitiated then begin watching themselves, and the cycle repeats and spreads. The zombies then go viral in real life.

If Berger’s study isn’t enough, consider the case of Upworthy. The feel-good-content site started in 2012, and just a year later it was competing with BuzzFeed to be the second most shared site on Facebook, with such clickable titles as “Watch a Teenager Bring His Class to Tears Just by Saying a Few Words,” “What a Service Dog Really Thinks of the Injured Vet Who Owns Him,” or “He Calls It A 'White-Knuckle Problem.' After Hearing The Statistics, I Couldn't Agree More.”

In his book, Contagious: Why Things Catch On, Berger goes on to argue that things also go viral because they have social currency, are memorable, and meet a certain standard of quality. Content that makes readers feel in the know -- be it through memes or allusions -- is more shareable because it creates an insider culture. Berger also points out that we share what we’re thinking about, and those are the things we can remember. Listicles are skimmable packets of useful, interesting information, which is partly why they’re so shareable. Lastly, quality content will always be shareable, and it’s how Upworthy has defended itself against accusations of being a sensationalist platform.

“Coming up with catchy, curiosity-inducing headlines wasn’t the reason Upworthy had those 87 million visitors,” argue the folks behind the site. “It was because millions of members of the Upworthy community watched the videos we curated and found them important, compelling, and worth sharing with their friends.”

The point here is that if you want to generate a buzz, improve your online presence, and increase your brand awareness, your content needs to be evocative and touch upon some primal emotion in the reader. Zombies prey upon fears that people don’t even know they have, which means you need to know audience better than it knows itself.

Just be sure to study their brains, not eat them.