Now that advertising is increasingly moving into the domain of social media, a key goal in marketing strategy has been to develop a framework for making things go viral. Campaigns such as Dos Equis' The Most Interesting Man in the World campaign, or Old Spice's The Man Your Man Can Smell Like campaign have significantly enhanced the reputation and visibility of these brands. Then there is the world of viral memes, where websites like I Can Has Cheezburger? can net a comparable traffic volume to The New York Times. The problem is that many of the ideas that go viral are ill-fitted to traditional marketing strategies (evidence: cats are rarely mentioned in marketing strategy books). Can classical marketing theory explain why the video of Susan Boyle or why PSY's Gangnam Style were such great hits and why other similar videos are not? In marketing, viral media is clearly a space that is getting a lot of attention, and any book that attempts to explain something significant about this space is certainly worth reading.

One such book is Jonah Berger's Contagious: Why Things Catch On. The book is distinguished from other explorations of what makes things cool and viral on its base in over ten years of empirical research the author has conducted at the Wharton Business School. The basic theory the book espouses is that there are six factors that contribute to something going viral. The six factors can be conveniently incorporated into the acronym STEPPS. Each of the chapters of the book deals with one of the factors. My short summary of each:

• Social Currency: People share what makes them look good and "in the know" to others.
• Triggers: People share things that they frequently encounter, and marketers need to ensure that ideas are triggered at the moment when they'll actually have impact on decisions.
• Emotion: People find emotions compelling, and Berger brings up the case of Susan Boyle's famous performance: when something is emotionally engaging it has a tendency to stick around.
• Public: Things need to be generally accessible to go viral. Berger brings up the example of the Apple laptop logo, which was deliberately designed to be seen properly by other people rather than the user.
• Practical Value: People like sharing things that their friends find useful.
• Stories: People like stories and will be more likely to share things that have an engaging narrative structure.

None of these six factors should be particularly surprising, and in fact one can find far more advanced and seminal works on each of these topics elsewhere (The New York Times review mentions the work of Malcolm Gladwell and the work of Chip and Dan Heath). However, Jonah's book adds an interesting and entertaining perspective. The book is particularly engaging when he refers to empirical evidence that debunks a commonly held assumption (although he rarely provides enough detail to evaluate that evidence), or when he shows examples of a lack of alignment between a viral strategy and a marketing goal, as in the case of goldenpalace.com's 2004 Olympic stunt. There are very few places you can go to get such an interesting and entertaining discussion of examples.

Another highlight of the discussion was Jonah's classification of emotions into high and low arousal varieties, as in this four-by-four matrix:

The thought behind this matrix is that if you want an idea to catch on emotionally, it is better to focus on the high arousal emotions, whether they be positive or negative, rather than the low arousal emotions. Berger notes that although we tend to want to produce the positive high arousal emotions in viewers, the negative ones can be at least as potent.

What makes something go viral? At the end of the read Contagious won't give you a detailed strategic blueprint, or provide in-depth philosophical, psychological or anthropological discussions, but it does provide a rich discussion of examples, and shows a broad range of issues people should take into account when attempting to make an idea go viral.

By @jfhannon, CEO at Justkul Inc., a research firm focused on the needs of strategy and private equity.