The most powerful predictor of what spreads online is anger.

The researchers found that while sadness is an extreme emotion, it is a wholly unviral one.

Photos were awe-some; they made us angry, or they surprised us.

Behind the scenes I work to crank up the valence of articles, relying on scandal, conflict, triviality, titillation, and dogmatism. Whatever will ensure transmission.

CNBC fell ass first into the perfect storm of what spreads on the web—humiliation, conspiracy theories, anger, frustration, humor, passion, and possibly the interplay of several or all of these things together.

You set up a mystery—and explain it after the link. Some analysis shows a good question brings twice the response of an emphatic exclamation point.

The most common play is to use girl, preferably one who looks like she might get naked, but it con be anything from a kitten to a a photo of someone famous. The technique can drive thousands or even tens of thousands of views to a video, helping it chart on most viewed lists and allowing it to spread and be recommended.

Study the top stories of Diff or MSN.com and you'll notice a pattern: the top stories all polarize people. If you make it threaten people's 3 Bs - behavior, belief, or belongings - you get a huge virus-like dispersion.