PubNub employs a combination of Google Closure Compiler Advanced Optimizations, maximum GZIP compression, and Memcache to enhance the performance and delivery of JavaScript files. This method involves optimizing JavaScript files using Google Closure, compressing them with GZIP at maximum compression, and storing them in Memcache or using a CDN for broader distribution. Modifications to headers are recommended to include only essential fields such as Content-Type, Content-Length, Content-Encoding, and Expires, with the addition of a Proxy Cache-Control header for better cache efficiency in remote areas. The aim is to reduce the payload size to under 4,000 bytes, with PubNub's library achieving a size of under 2,900 bytes, enhancing speed for a global audience. Additionally, the article highlights the importance of fast page delivery speeds due to their direct impact on revenue, emphasizing that even minor delays can significantly affect earnings, particularly on congested mobile networks.