1) Domain Driven Design (DDD) is an approach to software development that focuses on modeling a domain accurately. It represents knowledge, activities, and influences of a domain using objects. 2) DDD is better than traditional service/manager models because it avoids dependencies on specific implementations and improves communication between developers and customers. 3) In DDD, the domain layer is at the heart of the software and represents business concepts and situations using domain objects like entities, value objects, and services.