Christian Posta discusses the microservices architectural style, emphasizing its ability to break applications into small, autonomous services that enhance speed and scalability while tackling challenges like system complexity and security. He outlines the advantages and drawbacks of microservices, along with strategies for implementation, including the importance of high-performing IT teams and cloud-native practices. The presentation also covers tools and frameworks for managing microservices, such as Kubernetes and service meshes, advocating for experimentation and continuous learning in development.