“The Tipping Point is the biography of an idea.”
What is the idea?
The idea is that “[i]deas and products and messages and behaviors spread just like viruses do.”
In addition to describing how the spread of ideas is like the spread of viruses, Gladwell describes three kinds of people who are necessary for the spread of an idea: Connectors, Mavens, and Salesmen.
This is an excellent book for anyone who is interested in Word Of Mouth marketing, by the way.