Families, friends, sororities, civic and professional organizations. Any group that has a positive or negative influence on a persons attitude and behavior. Affinity marketing is focused on the desires of consumers that belong to reference groups. Marketers get the groups to approve the product and communicate that approval to its members. US is not a classless society.
Social class influences many aspects of our lives.
IE upper middle class Americans prefer luxury cars Mercedes. Lower class people tend to stay close to home when shopping, do not engage in much prepurchase information gathering. Stores project definite class images. Family, reference groups and social classes are all social influences on consumer behavior. All operate within a larger culture.