Azure Functions are a serverless on-demand execution of code based on external events like HTTP requests, chat messages, etc., and Fauna Cloud is a database designed for these serverless runtimes. Fauna Cloud offers strong consistency and ACID transactions, pay-as-you-go utility pricing model, and can scale up and down without attention required from users. It allows developers to start developing right away with no provisioning needed, and provides lower costs compared to other options. The post demonstrates how to connect to Fauna Cloud from JavaScript running in Azure Functions, enabling the creation of a globally consistent database accessible from all cloud providers. This setup enables remixing services from different clouds, allowing for arbitrage capabilities and pricing across any combination of platforms.