First consider what consumer trends are.
From the business dictionary: "Habits or behaviors currently prevalent among consumers of goods or services. Consumer trends track more than simply what people buy and how much they spend. Data collected on trends may also include information such as how consumers use a product and how they communicate about a brand with their social network."
Then consider why they would need to know the habits and behaviors of people who might potentially buy their product.
Small business owners need this information in order to market their products effectively to their target audience.