The mirror stage creates the division between the whole person who we see in the mirror and the fractured person we are. So we are constantly on a search to fill this gap to find the delight of being whole. Our perception of the self depends on what images we use to fill in this lack. We depend on the existence of the Other to fill in the gap of our desires, to create, if only for a moment, the wholeness before our subjectivity, before there was an Other. How this relates to ads and Otherness can be explained by the importance of the gaze, or more specifically, the image of the Other.
Images constitute the self.
Images of the literal Other create both a separation because it is through that difference that we are constituted but also as we look toward the Other, it is with the desire of being a unified self. So we depend on the Other both to create the self through difference and somehow to fill up the gap created by our subjectivity because the Other represents this unified self we have lost. We look to ads with their commodities and images of Otherness to constitute the self and somehow fill in the gap between our fractured identity and the ego-ideal.