More than 425 million people worldwide use Gmail, the web-based email service by Google. Known for its ease of use and intuitive interface, Gmail grew rapidly at launch, but few people would have seen the service’s key features if it weren’t for one of the most successful word-of-mouth marketing campaigns in history.

Gmail started as a close, work-only email system for Google employees. The company launched it to the public in a limited, invite-only release in April of 2004. Google asked many of its employees to send out invitations to their friends and family to join the closed beta test of Gmail. Occasionally, those recently invited friends and family would also get the chance to distribute invitations. The use of Gmail went from being part of an exclusive network of people in-the-know, to being part of an international phenomenon that connected millions of people.

This was a great accomplishment considering that practically everyone who received an invitation to try Gmail had no need of it because they already used a different email system. By relying on users to recommend Gmail to friends and family, rather than raising awareness about the service through more traditional, outbound advertising, Google convinced people to support a product despite a lack of demand.

What is word-of-mouth marketing?

As the name implies, word-of-mouth marketing is any instance where consumers share information about a product or organization with one another, whether by talking or through some other medium. Internet communication, especially social networking, is a significant part of modern word-of-mouth marketing. Though traditional word-of-mouth relies on consumers talking to one another in a direct, personal context like an in-person conversation or a telephone call, Internet-based word-of-mouth uses a variety of platforms that may not involve speaking at all.

In the case of Google’s viral Gmail campaign, the company used word-of-mouth in real life and via Internet-based networks to spread information about the new email service. Google allowed the campaign to continue to spread by allowing current users to distribute new invitations themselves. The company continued to grant new users the ability to send invitations to their own social networks until Gmail became available publicly.

Advantages of word-of-mouth marketing?

According to Nielsen, 92% of people around the world said they trust recommendations from friends and family (earned media) above all other forms of advertising.

Consumers are more emotionally bonded to a company when they feel they are listened to by the company. That is why many companies will have sales representatives discuss their products and services with consumers personally or through a feedback phone line. This kind of interaction, as well as promotional events, can stimulate conversations about a company's product.

There is a significant temptation to fabricate word-of-mouth marketing. Accordingly, the Word of Mouth Marketing Association (WOMMA) has crafted a code of ethics for the industry, the best word-of-mouth marketing strategies are "credible, social, repeatable, measurable, and respectful" and there is no excuse for dishonesty. WOM marketing expert Andy Sernovitz has boiled down WOMMA's code of ethics into three key rules to avoid issues:

Say whom you are representing (always disclose a relationship)

Say only what you believe (be honest with an opinion)

Never lie about who you are (be honest about your identity)

Who implements word-of-mouth marketing campaigns?

Any organization that can encourage people to spread information about a product, a cause, or the organization itself can use word-of-mouth marketing. It is useful in for-profit endeavors as well as in non-profit causes like political campaigns.

An apartment management company, for instance, could encourage tenants to refer their friends and family to the company if they are in the market for a place to live. The company could give incentives for these referrals by offering tenants a cash bonus or some other benefit if someone they refer to the management company signs a new lease.

Word-of-mouth is also a popular technique used by medical professionals to share patients with different specialists. A doctor could suggest a particular dental practice to patients, just as that dental practice could refer patients to specialists like orthodontists and oral surgeons. This is often based on the existing professional networks of the doctors and dentists, as well as each practice’s reputation. 

Political campaigns are especially dependent on word-of-mouth. In addition to convincing individuals to vote for a particular candidate or issue, they also encourage people to talk to others about doing the same. This is frequently accomplished by providing people with content they can share, like email newsletters, online videos, and social networking pages.