Going viral isn't always a stroke of luck and timing although that has allot to do with it. The art of going viral is a combination of many things but ultimately it's all about doing something worth sharing in a brilliant unsuspecting way.
Everything starts with story, and the same holds true for online videos. Sometimes going viral happens by chance but if the foundation of the video stands on a well-written thoughtful story, viral will only be one of the many successful outcomes.
Last year the Bullitts did an excellent job on this piece featuring Rosario Dawson. It's the official music video so spoiler: it is staged. But you wouldn't know that by the execution. Well done. Also check out more from the Bullitts here.