Word of mouth
Also called: word-of-mouth marketing, WOM, WOMM, recommendations, referrals
Definition
Word of mouth is customers recommending a product to other people, in conversation, messages or online communities. Nielsen's 2021 survey found people trust recommendations from people they know more than any other channel.
Word of mouth is the oldest growth channel: one person telling another that something is worth using. It is also still the most trusted. In Nielsen's 2021 Trust in Advertising study of more than 40,000 consumers, 88% of global respondents said they trust recommendations from people they know more than any other channel.
How it works
Word of mouth needs three things: a product people are happy with, a moment when someone asks for a recommendation, and a reason the happy user remembers you at that moment. Marketing can help with the second and third. It cannot fake the first for long.
Forms it takes:
- Private: a colleague's Slack message, a friend's text. Mostly invisible to analytics; see dark social.
- Public: reviews, social posts, forum replies. Visible and searchable.
- Structured: referral programs that reward sharing.
Why it matters for marketers
Word of mouth lowers customer acquisition cost because you do not pay per recommendation, and it brings buyers who arrive with trust already in place. It also compounds: every happy customer is a possible source of the next one.
The catch is control. You cannot buy genuine word of mouth. The FTC's rule announced in August 2024 bans fake reviews and testimonials, undisclosed insider reviews, and paying for reviews conditioned on a particular sentiment. Incentives are allowed only within those limits.
How it plays out on Reddit
Reddit is word of mouth with a search index. When someone posts "what do you use for X?", the replies are recommendations from people with experience, and unlike a text between friends, they stay public. Those threads rank on Google and are the most-cited source in AI search (Peec AI, US data, March 2026), so one recommendation keeps getting read by strangers for years.
That changes the job:
- Make it easy to be recommended. A clear name, a clear "who it's for" and honest pricing make it easy for users to mention you accurately.
- Show up where people ask. When a thread asks for exactly what you sell, a helpful reply from the founder, clearly disclosed, is fair game in most subreddits. Check the rules first.
- Never fake it. Posting praise for your own product from alt accounts is astroturfing. Reddit bans it, and it misleads the people you want as customers.
Monitoring helps too. Knowing when someone recommends you, or a competitor, lets you thank them, answer follow-ups and fix problems people raise. See Reddit social listening.
Common mistakes
- Asking for "honest reviews" with a reward tied to positivity. That is the conditioned-incentive problem the FTC rule targets.
- Ignoring negative word of mouth. A calm, specific reply often does more than ten positive mentions.
- Assuming it cannot be measured. Ask new users where they heard about you and track public mentions.
Frequently asked questions
Why is word of mouth so effective?
People trust recommendations from people they know more than any other channel, according to Nielsen's 2021 study, and recommendations come at the moment someone is asking.
Can you pay for word-of-mouth marketing?
You can run referral programs and send products to reviewers, but disclosures are required and the FTC bans fake reviews and rewards tied to a particular sentiment.
Is Reddit word of mouth?
Largely, yes. Recommendation threads on Reddit are public word of mouth that keeps being read through Google and AI search.