The document discusses three classic use cases for cloud computing: single tenant SaaS, multi tenant SaaS, and online digital marketing. For single tenant SaaS, it describes challenges like software built for traditional hardware and the need for automated infrastructure deployment. For multi tenant SaaS, it mentions scalability and multi-region deployment challenges. For online digital marketing, it discusses issues like heterogeneous environments, capacity planning, and secure access without sharing credentials. AWS is presented as a solution to address the infrastructure needs for all three use cases.