Generally speaking, cultural models are shared perceptions and attitudes about how the world works. They are mental tools used by to process and organize information, make decisions, and guide behavior. People construct simple cultural models of how the world works and use these models to guide decision-making, behavior and as an aid in understanding novel or unfamiliar ideas. We call them cultural models, instead of just mental models, because they are shared across social groups. Cultural models are taken for granted and operate below the level of individual consciousness.
But the individual is not wholly defined by just personal social, cultural, and political beliefs but also functions within a group of individuals. Within these groups, they assimilate a potentially wide variety of different social factors, which may or may not differ from their own. Also, the group itself can vary in degrees of complexity, styles of interaction, and so forth, resulting in highly dynamic and emergent modes of behaviors.
So why does it matter? It matters because cultural modeling allows you to understand how systems and elements therein produce results that are often unexpected when deriving information from traditional research. And that means more opportunities to make money.