Viral marketing works famously on the Internet because instant communication is easy and inexpensive. The digital format makes copying simple. From a marketing standpoint, you must simplify your marketing message so it can be transmitted easily and without degradation. Short is better. The classic is: “Get your private, free email at http://www.hotmail.com.” The message is compelling, compressed, and copied at the bottom of every free email message.
According to a paper by Duncan Watts and colleagues entitled: "Everyone's an influencer", the most common risk in viral marketing is that of the influencer not passing on the message, which can lead to the failure of the viral marketing campaign. A second risk is that the influencer modifies the content of the message. A third risk is that influencers pass on the wrong message. This can result from a misunderstanding or as a deliberate move.