The Pareto Principle in business refers to the way 80 percent of a given business's profit typically comes from a mere 20 percent of its clientele. Business owners who subscribe to the 80/20 rule know the best way to maximize results is to focus the most marketing effort on that top 20 percent.
The rule is often used to point out that 80% of a company's revenue is generated by 20% of its customers. Viewed in this way, it might be advantageous for a company to focus on the 20% of clients that are responsible for 80% of revenues and market specifically to them.