Between 1996–1997, Hotmail was one of the first internet businesses to become extremely successful utilizing viral marketing techniques by inserting the tagline "Get your free e-mail at Hotmail" at the bottom of every e-mail sent out by its users. Hotmail was able to sign up 12 million users in 18 months. At the time, this was historically the fastest growth of any user based media company. By the time Hotmail reached 66 million users, the company was establishing 270,000 new accounts each day.
In mid 2016, an Indian tea company (TE-A-ME) has delivered 6,000 tea bags to Donald Trump and launched a video on YouTube. and Facebook The video campaign received various awards including most creative PR stunt in Southeast Asia after receiving 52000+ video shares, 3.1M video view in first 72-hour and hundreds of publication mentions (including Mashable, Quartz, Indian Express, Buzzfeed) across 80+ countries.
Utilizes existing communication networks. Most people are social. Nerdy, basement-dwelling computer science graduate students are the exception. Social scientists tell us that each person has 8 to 12 people in her network of friends, family, and associates. A person’s broader network may consist of scores, hundreds, or thousands of people. A waitress, for example, may communicate regularly with hundreds of customers in a given week.
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.