The surprising impact of word of mouth marketing in a digital age

Mark Schaefer
6 min readAug 28, 2023

Ed Keller is one of my marketing heroes. He’s considered the godfather and preeminent authority on word-of-mouth marketing and he wrote the seminal book on the subject in 2003, The Influentials. Ed is still researching the subject today as a professor at the University of Pennsylvania.

To illustrate my Ed Keller fanboy level, I used to drop by his office whenever I taught at Rutgers University just for a chance to meet him. I never did. So what a thrill when one day Ed reached out to connect to me on LinkedIn!

Since then, we have collaborated in a few ways, including a conversation within my RISE marketing community.

Word-of-mouth marketing has never been more relevant and never less understood. If this is a new idea to you, this article on the difference between influencer marketing and word of mouth might be a great place to start.

So let’s get to Ed. Here are a few excerpts from my conversation with him and how word-of-mouth marketing is especially relevant in the digital age. These are quotes from Ed, which have been edited for brevity:

What is an influential?

For a long time, we have had a misconception about how influence works. These are certain people — about 10 percent of the population — who are interested in acquiring knowledge, keeping up with things that are new. They like to talk to people about what they learn. As they acquire this new information, the process gets turned around, and they get sought out for their advice since they seek so much knowledge.

So it’s not any kind of pushy influence like you would want to avoid. An influential is actually someone you’d like to run toward as a trusted friend. We live in a complicated world, and it is a complicated consumer marketplace. We need somebody to make sense of it for us. That is the role of the influential and word-of-mouth marketing, as it has been throughout history, and especially now in the digital age.

Trust in traditional institutions has plummeted. And that doesn’t just count for trust in advertising. It’s trust in corporations, government, and media.



Mark Schaefer

Keynote speaker, marketing strategy consultant, Rutgers U faculty and author of 10 books including KNOWN, Marketing Rebellion, and Belonging to the Brand!