This document discusses various metrics, tools, and techniques for measuring and improving website performance. It outlines common metrics like first byte, first paint, and page load time. It also lists popular profiling tools like WebPageTest, FireBug, and Chrome Developer Tools. Additionally, the document discusses the differences between synthetic monitoring and real user monitoring. Finally, it provides recommendations for performance best practices such as reducing page size, optimizing images, leveraging caching, and optimizing JavaScript.