Word-of-mouth can be your greatest asset or your worst enemy. Maybe you post an entertaining video about the razors you'd like to sell the general population and it ends up going viral and launching your company (Dollar Shave Club). Or on the other hand, maybe a major crisis occurs involving your brand and you're not equipped with the knowledge of communicating effectively across the social platforms used by your customer base (Asiana Flight 214).
On that note, have you ever wondered what fuels word-of-mouth movements?Contagious, a book written by Jonah Berger, explains why things catch on and how these powerful movements ignite. He focuses more on the art of creating campaigns that go viral, as I mentioned above with the Dollar Shave Club example, but his concepts also parallel with the needs to protect one's brand as seen with the Asiana example above.
There is no perfect formula for taking your content viral, but this book will give you the variables needed to make that social currency we converse with on a daily basis, which will help provide the tools for any advertiser to craft contagious content.