"Tipping point" is a term drawn from the field of epidemiology, the study of the spread of diseases through a population. The tipping point in an epidemic such as AIDS is the point at which there are enough carriers of a disease or some other factor influencing the contagion to allow an explosion that will infect a large number of people. Similar concepts are used in the social sciences, where ideas that spread through cultures like germs are called memes.
Gladwell presented his ideas, which add examples and analysis from business areas such as advertising and television broadcasting, in a 1996 article in The New Yorker magazine, where he is a staff writer. They met with a ready reception, and, since then, the concept of the tipping point itself has tipped. Gladwell's book became a bestseller, and the journalist has been the subject of numerous articles since its publication.
Part of the tipping point's appeal is the simple way in which Gladwell describes it. He says there are just three basic rules that govern how products become hot sellers, ideas become popular, and other epidemics come into being. One of the rules, which he calls the "Stickiness Factor," states that an idea has to be memorable or a product has to be of durable value to effect a tipping-point change. Another of Gladwell's rules, the "Power of Context," essentially states that nothing happens in a vacuum, and the surrounding environment has a lot to do with when tipping points are reached and what happens when they are.
Perhaps the most interesting of the rules is the "Law of the Few." It refers to the fact that, generally, most of the effect of anything is produced by a relatively small number of the effectuators. It's better known as the 80-20 rule, or the "Pareto Principle," which explains why, for instance, roughly 20 percent of a typical company's customers produce approximately 80 percent of its profits. Rather than leave it at that, Gladwell identifies three types of people whose influence is out of proportion to their numbers. In other words, these are the few you need to reach if you want to pursue your own tipping point.