One of the goals of Play2 architecture is to provide a programming model for what is called Realtime Web Applications.
Realtime Web Applications are applications that make use of Websockets, Server Sent Events, Comet or other protocols offering/simulating an open socket between the browser and the server for continuous communication. Basically, these applications let users work with information as it is published - without having to periodically ping the service.
There are quite a few web frameworks that target the development of this type of application: but usually the solution is to simply provide an API that allows developers to push/receive messages from/to an open channel, something like:
