I found this Ina Garnefeld et al. Study Very insightful. Please note particularly
“Businesses have long recognized the power of word of mouth: When customers recommend a restaurant or clothing store to friends, for example, they’re helping that business gain new clientele, at little or no cost.
But this paper looks at word of mouth from an opposite perspective, and finds an additional payoff: In telling friends about a favored business, service, or product, existing customers find that their own feelings of loyalty have increased.”