The document discusses the evolution of real-time web applications from early PHP polling techniques to newer HTML5 capabilities. It notes that in 2000 PHP developers used simple polling via sequential Ajax requests to implement chat applications, which placed heavy loads on servers. Comet techniques from 2006 used long-polling to reduce loads but increased memory usage. Modern HTML5 features like WebSockets now provide browsers with true real-time capabilities comparable to desktop applications, allowing for responsive real-time web apps using only HTML, CSS and JavaScript.