In light of the recent occurrences of the H1N1 (swine flu), it may seem counter-intuitive to think that contagion is ever a good thing.

My friend, you could not be more wrong.

As marketers in a digital world, we seek to be ever-contagious so that our clients, friends and fans (Facebook and otherwise) willingly spread the word to all who may need our services.

Specifically in the online realm, going viral is akin to hitting the motherlode. It's usually the most cost-effective way to let people know about your offerings... it takes advantage of word-of-mouth referrals, which are far more likely to elicit a change in consumer behavior than most other forms of promotion... and it warms up a cold call faster than you can melt an Italian ice in July.

So what's the trick? How do you know when you've reached American Idol fame or launched the next "Elf Yourself" promotion? That is the $64,000 (or more) question.

There are dozens of theories floating around about what makes a winning viral campaign, and many professionals in the marketing and technical world claim to know the secret, but the truth is, no one really has the definitive answer. (If they did, they'd be packaging that knowledge and touting their successes on an infomercial.)

What do we know? The most popular viral campaigns often include three key elements:

• You're just like me! Viral marketing depends on building an instant emotional connection with your audience so they can identify with you. Think about American Idol and America's Got Talent: viewers are glued to those shows because those folks are -- quite literally -- from our own neighborhoods. The recent appearances of Susan Boyle on Britain's Got Talent demonstrate that phenomenon in spades. (Really now, she was amazing, wasn't she?)
• When it comes to viral, we're all from Missouri. Most of us find it easier to connect with a visual message (so say our Midwestern friends in the "Show Me State"), and the most successful viral marketing campaigns use video to build an instant bridge with the audience. Whether that video is a homegrown work showing a bride's wedding gaffe or an animated dancing elf, the video makes the story.
• Did you hear the one about...? The third common denominator to successful viral campaigns is that they tell a story with a believable premise. Rather than predicate the story on a UFO landing or the discovery of Atlantis, they start with something credible and familiar like a husband giving his wife a vacuum cleaner for their anniversary. (Raise your hand if you see someone you know.)

Exactly how to combine these elements is the trick that everyone's trying to figure out. But when you hit on the right combination, it's just like Vegas, baby: lights flash, bells sound, beautiful Vanna-like models shower you with prizes and Ed McMahon himself brings you a giant check.

Well, almost.

Next month, we'll talk about tags and bookmarking as a way to enhance your online experience.