Viral marketing takes its name from something that we usually hope to avoid: a virus. The term “viral” marketing evokes the rapid and contagious way a virus spreads and infects people. In PR and marketing, viral marketing takes advantage of “network effects” — especially social media networks like YouTube, Twitter, Facebook and so on. Viral marketing is actually not new — in fact, some argue that its origins are old-fashion “word of mouth” marketing.
This article, “The Virus of Marketing“, was published in Fast Company back in 1996 — long before the laungh of Facebook, Twitter and YouTube. In 2007, Time magazine described the presidential campaign of candidate Barack Obama as “viral”. See that article here: “Obama’s Viral Marketing Campaign“. For an updated definition of viral marketing, see marketing guru Seth Godin‘s blog post here: “What Is Viral Marketing?” Also see Brian Solis’ refined definition here: “Redefining Viral Marketing“.
Several years ago newspapers like the Sunday Times (see link here) were listing top viral video campaigns. Today viral campaigns today are much more sophisticated. See here for Mashable’s “Most Shared Ads of 2014“. Also see “Top Viral Ads of 2014“. For an account of perhaps the most talked-about — and most effective — viral campaign in the past couple years, see this article on the Old Spice viral videos. This article provides a factoid and an interesting analysis of why the Old Spice campaign was such a success.
For an academic study of viral marketing, see this paper, “The Rise of Viral Marketing Through the New Media of Social Media“.