Market segmentation involves dividing a heterogeneous market into homogeneous sub-units. It divides the overall market for a product into segments based on variables like geography, demographics, psychographics, and behavior. Effective segmentation allows companies to target specific segments, develop appropriate marketing strategies for each segment, and improve marketing efficiency. The key advantages of segmentation include helping target the right customers, tapping selected markets effectively, identifying less satisfied customer segments, and making marketing more efficient.