1. Consumer
The ultimate user of goods, ideas or services. Also the buyer or decision maker, for example, the parent selecting children's books is the consumer.
2. Consumer Behavior
The behavior of the consumer or decision maker in the market place of products and services. Library user behavior is often captured in library literature under use studies.
3. Demarketing
The process of reducing the demand for a product--or decreasing consumption.
4. Demographics
Objective characteristics of consumers such as age, income, education, sex or occupation (Assael)
5 .Elasticity
The degree that an economic variable changes in response to a change in another economic variable. For example how much library use changes according to how far an individual must travel for library services.