A single product rarely satisfies an entire market equally well. Market segmentation divides a broad market into subsets of consumers who share common needs, characteristics, or behaviors. Segments may be defined by demographics, geography, psychographics, or usage patterns. Once segments are identified, a firm can choose which to target and how to position its offer for each.

Effective segments are measurable, accessible, substantial, and actionable. Overly fine segmentation can become impractical; overly broad segmentation wastes the opportunity to differentiate. The same customer may belong to different segments depending on the product category or the occasion.

Segmentation is the foundation of targeted marketing. It allows more precise messaging, product development, and channel selection. Firms that understand their segments can allocate resources where the return is highest and can avoid competing solely on price in undifferentiated markets.