This chapter features Rebecca Walls, author of a book entitled The Divine Secrets of the Ya-Ya Sisterhood in 1996. Upon its initial release, the book sold moderately. Later on, however, the book sold numerous copies making it one of the most purchased books at the time. In this chapter, Gladwell tries to explain the phenomena behind the sudden magical increase in sales and popularity of the book which saw the author sell close to 2.5 million copies in February 1998. Gladwell attributes this change to the power of word-of-mouth, which he states, began with the book club members. The chapter uses various examples to shine a light on similar events that start moderately and eventually become common among the majority. For instance, the author direct readers to think about how religious movements came to be. He argues that religious movements were propelled by a few skillful but powerful groups of people who persuaded people into following their ideologies.

The most obvious reason why The Divine Secrets of the Ya-Ya Sisterhood suddenly sold millions of copies is that it was beautifully written and the fact that it told a story of friendship between a girl and her mother that resonated with many. Secondly, it could be because the author herself was a renowned actress; therefore, she was well positioned to be a ‘salesman.’ Thirdly, Gladwell explains that the book could also have become popular because of contextual power. In this chapter, Gladwell expounds on the various human cognition studies that conclude that the brain has the capacity to divide any given stimuli into categories. For instance, it is believed that on average, a person has the capabilities of distinguishing approximately six notes in music before they can get confused. This scenario is better explained through phone numbers. Most people easily remember phone numbers that are seven digits long and experience difficulties retaining longer numbers. Gladwell elaborates that just as the human brain is limited to seven numbers, it is also limited to 150 social relationships.

Indeed, this hypothesis has been proven effective by Wilbert Gore, who despite owning a multi-billion company, organizes and operates as a small business. According to Gladwell, Gore’s organization is valid because there are no cases of redundancy and overlapping is minimized. The advantage associated with the 150 rule is the fact a group can easily be divided into sectors or different tasks. For instance, an organization can have individuals specializing in production while some take on customer service depending on their fields of study and areas of specialization.

In short, Gore created an organized mechanism for sharing information from one individual to the other throughout an organization. Therefore, through the rule of 150, an organization can extensively rely on the associations of peer pressure and memory. Failure to adhere to the 150 limits will only result in significant impediments including individuals failing to agree to operate as a single unified unit.