Market segmentation involves dividing a heterogeneous market into homogeneous subgroups based on characteristics like geographic location, demographics, psychographics, and behaviors. Effective segmentation provides benefits like identifying market potential and adjusting resources profitably for each subgroup without losing the overall market. Key requirements for segmentation include measurability, accessibility, and substantiality of the identified subgroups. Common variables used in segmentation are geographic, demographic, psychographic (lifestyle and personality), and behavioral (benefits sought, usage rates, loyalty). The segmentation process involves assessing differences between customer groups, identifying factors to disaggregate customers, analyzing marketing program possibilities for each subgroup, selecting the most beneficial segments, and estimating purchase levels.