This document discusses client-side performance measurement and optimization techniques for Rails applications. It recommends measuring performance using the clientperf gem to identify opportunities for improvement. Specific techniques mentioned include making fewer HTTP requests by combining components, gzipping components to reduce file sizes, adding expires headers to eliminate unnecessary requests, placing stylesheets at the top of pages to allow earlier rendering, and placing scripts at the bottom to avoid blocking other downloads. The document notes this is just a starting point and provides additional resources for further optimization.