Let me cut to the chase:
The take-away message from this work is that if you want your video, press release, news story, blog post or tweet to reach as many people as possible, there are specific things you can do to increase its chances of being widely shared.
Make it emotional - ideally triggering emotions like anger, anxiety or awe that tend to make our hearts race; and if you can, make it positive. This may be more even effective than other methods that are currently in wide use like targeting "influentials," or opinion leaders.
Crafting contagious content, as this research suggests, may provide more bang for your buck and create more reliably viral content.