The document discusses various techniques for improving web UI performance including minification, obfuscation, compression, combination, setting expiration headers, CSS image sprites, parallelizing downloads, using content delivery networks, browser and web-based performance tools, and specific techniques for Java, .NET, PHP, and Drupal web applications. Some examples include using pack:tag in Java to combine scripts and stylesheets, the ExpiresFilter in Tomcat, the jscssconsolidate tool for .NET, and the phpminify library for PHP. The goal is to reduce page size, number of requests, and load time to improve user experience.