From Contagious, (c) 2013, Jonah Berger, p. 10-11, quoting directly:
Help me out with quick pop quiz. What percent of word of mouth do you think happens online? In other words, what percent of chatter happens over social media, blogs, e-mail, and chat rooms?
If you’re like most people you probably guessed something around 50 or 60 percent. Some people guess upward of 70 percent, and some guess much lower, but after having asked this question of hundreds of students and executive, I find that the average is about 50 percent.
And that number makes sense. After all, social media have certainly exploded of late.
Millions of people use these sites every day, and billions of pieces of content get shared every month. These technologies have made it faster and easier to share things quickly with a broad group of people.
But 50 percent is wrong.
Not even close.
The actual number is 7 percent. Not 47 percent, not 27 percent, but 7 percent. Research by the Keller Fay Group finds that only 7 percent of word of mouth happens online.
Most people are extremely surprised when they hear that number. “But that’s way too low,” they protest. “People spend a huge amount of time online!” And that’s true.
People do spend a good bit of time online. Close to two hours a day by some estimates. But we forget that people also spend a lot of time offline. Most than eight times as much, in fact. And that creates a lot more time for offline conversations.
We also tend to overestimate online word of mouth because it’s easier to see …. But we don’t think as much about all the office conversations we had over the same time period because we can’t easily see them.
Jonah Berger is the James G. Campbell Assistant Professor of Marketing at the Wharton School at the University of Pennsylvania. He has published dozes of articles in top-tier academic journals, and popular accounts of his work have appeared in places like The New York Times, The Wall Street Journal, The Washington Post, Science, Harvard Business Review, Wired, Businessweek, and Fast Company. His research has also been featured in the New York Times Magazine’s annual “Year in Ideas” issue.
2019 Update: Note that from 2012 to 2019 Millennial Facebook usage has remained steady at 82-84%. Gen X Facebook usage is up slightly, from 67% to 74%. Millennial’s use of Instagram, Pinterest, and LinkedIn has essentially doubled, from the teens to 37%, 28%, and 27% respectively. This rough doubling is mostly true for Gen X as well, but lower overall.
Which means: Starting from the 7% number in 2013, there would be no good reason to assume that the 7% has more than tripled, which is being very generous to social media. It would have to be that the ratio here is no more than 80% to 20% in favor of offline word of mouth.
See April 10, 2019, Andrew Perrin and Monica Anderson. Adults using social media, including Facebook, is mostly unchanged since 2018. Note that this article is based on Pew Research Data, which also was the source of the Facebook usage statistic. (Survey conducted January / February of 2019)