"It is safe to say that word of mouth is-even in this age of mass communications and multi-million-dollar advertising campaigns-still the most important form of human communication. Think, for a moment, about the last expensive restaurant you went to, the last expensive of clothing you bought and the last movie you saw. In how many of those cases was your decision about where to spend your money heavily influenced by the recommendation of a friend? There are plenty of advertising executives who think that precisely because of the sheer ubiquity of marketing efforts these days, word-of -mouth appeals have become the only kind of persuasion that most of us respond to anymore."

The Tipping Point: How Little Things Can Make a Big Difference, author Malcolm Gladwell