The mortise permits the connection and transfer of meanings within an ad. It exists for this purpose. As an element of advertising design, the mortise prompts the appearance of connection between a product as signifier and an image as signified, or vice versa.
The mortise is usually arranged to direct a transfer of meaning between a brandname and a cultural representation of an object of desire.
When we read the mortise in ads, we have learned to look for a transfer of meaning between image and product. We expect the appearance of interchangeability between the product and the mediated visual imagery, such that either can come to stand for the other. This kind of narrative or story even permits us to infer a causal path running from product to the visually signified meaning of desire.
The mortise steers viewers toward the performance of three interpretive procedures we have already discussed: abstraction, equivalence and reification.
In this regard, contemporary advertising forms using the mortise reproduce a reading practice that mirrors commodity fetishism at very deep levels of communicative competence.
In ads, the mortise is a tool for constructing commodity signs -- i.e., the joining of product as signified and image as signifier. In today's advertising, the mortise has fallen out of some favor because it is so obvious in directing interpretation. Today's most successful commodity signs (the Nike swoosh, the Guess logo, the Benetton logo, etc) have actually formally abandoned the mortise in favor of allowing their brand sign to function as its own mortise.
As a device permitting a language of images to be turned to accommodate a language of value, the mortise literally becomes a 'production tool' in the articulation of sign values.