Understanding sharing behavior is big business. As consumers become increasingly blind to traditional advertising year on year, the push is on to go beyond simple pitches to tell engaging stories. And increasingly, the success of these endeavors is measured in social shares. Why go to so much trouble? Because, as a brand, every share I receive represents another consumer I've reached—all without spending an additional cent.

Because of this value, several researchers have examined sharing behavior in the hope of understanding what motivates it. Among the reasons researchers have found are the following:

• To provide practical value to others (an altruistic motive)
• To associate ourselves with certain ideas and concepts (an identity motive)
• To bond with others around a common emotion (a communal motive)

With regard to the last motive, one particularly well-designed study looked at the 7,000 pieces of content from the New York Times to examine the effect of emotion on sharing. They found that simple emotional sentiment was not enough to explain sharing behavior, but when combined with emotional arousal, the explanatory power was greater.

For example, while sadness has a strong negative valence, it is considered to be a low arousal state. Anger, on the other hand, has a negative valence, which is paired with a high arousal state. As such, stories that sadden the reader tend to generate far fewer stories than anger-inducing stories. Is it any wonder then that much of the fake news that plays such a large part in politics these days comes in this form? Following image shows the same result:

This covers the motivational aspects, but if we hold those factors constant, how do other attributes affect the virality of a piece of content? Some of these factors could include the following: headline wording, headline length, headline parts of speech, content length, social network of post, the topic, the timeliness of the subject matter, and so on. Without a doubt, a person could spend their entire life studying this phenomenon. For now, however, we'll just spend the next 30 or so pages doing so. From there, you can decide whether you'd like to take it further.