1. Direct marketing involves sending targeted messages directly to consumers through methods like email, telemarketing, and mail. It is more effective than mass marketing as it focuses on specific customer groups. 2. Data mining techniques like supervised classification can be used to analyze customer data and classify customers as loyal or unloyal for direct marketing purposes. Decision trees are a popular technique to visualize customer classifications. 3. Building accurate customer classifications is challenging due to issues like imbalanced class distributions in the data. Ranking and lift analysis can help address these issues and identify the most promising potential customers to target.