The document discusses Comet and DWR (Direct Web Remoting). It provides an overview of Comet, which allows for long-lived HTTP connections to enable low-latency data delivery. It discusses various Comet techniques like forever frames, long polling, and HTMLFile. It also covers challenges of implementing Comet and how frameworks like DWR and protocols like Bayeux help address these. DWR allows for easily calling Java objects from JavaScript and updating pages in real-time.