This document summarizes cloud platforms and their categories. It discusses that cloud platforms allow developers to create and run applications, store data, and access resources on demand. Cloud platforms are categorized as either public clouds run by large companies or private clouds run solely for a single organization. Within public clouds, platforms can provide infrastructure resources for complete control (IaaS) or pre-built platforms for specific uses like web apps (PaaS). Major cloud platform providers are mentioned like Microsoft, Amazon, Google, and Salesforce.