Answer:
The Heavy users of a business are those people who comprise about 20% of the business's consumers and yet buy so much that they bring in about 80% of the business's revenue.
Heavy users also have an impact on light users because they can market the goods to light users whether indirectly or directly when they use so much of a business's goods and services.
It is therefore very important that the business knows of these heavy users so that they can focus marketing strategies on them as well as to offer them incentives that will keep them satisfied and coming back for more because if they don't act and they lose their heavy users, their revenues will see a significant drop.