"Testing for Fragmentation" is a blog series that explores the importance of cross-browser testing for ensuring compatibility in software development and testing. Despite open standards from W3C, browser fragmentation remains an issue due to different design philosophies among vendors. Each vendor interprets these standards differently, leading to variations in end-user experience across browsers. Cross-browser testing is crucial as it helps developers account for differences in browser layers such as the engine, features, support for popular web technologies, and update frequency. Continuous testing for cross-browser compatibility minimizes errors and ensures a consistent quality experience for users regardless of their browser choice.