The Blumler & Katz theory is the understanding of what the audience does for the media not what the media does for the audience. It is the integration that the audience does for the media that helps sales, for example, buying of the product

Uses and gratifications

Uses and gratifications theory (UGTtheory) is an approach to understanding why and how people actively seek out specific media to satisfy specific needs. UGT is an audience-centred approach to understanding mass communication, Unlike many media theories that view media users as passive, uses and gratifications sees users as active agents who have control over their media consumption