8. Why is word of mouth so important for marketers? Consumers are influenced by many sources—marketing and nonmarketing, and those that are delivered through the mass media and those that are delivered personally. Consumers regard nonmarketing sources as more credible than marketing sources. Information delivered personally has less reach but more capacity for two-way communication compared with information from mass media sources. Marketers may want to target opinion leaders, online and offline, who are sources of influence because they are experts in a product category.

Reference groups, people with whom individuals compare themselves, may be associative, aspirational, or dissociative;

they can be described according to their degree of contact, formality, homophily, group attractiveness, density, identification, and tie-strength. These influence sources exert normative and informational influence. Normative influence tends to be greater for products that are publicly consumed, considered luxuries, or regarded as a significant aspect of group membership.

Normative influence is also strong for individuals who tend to pay attention to social information and when groups are cohesive, members are similar, and the group can deliver rewards and sanctions.