This is a simple chat application written in javascript using Meteor platform.
You can have a look at the working application here
This application was written to get started with Meteor, and also to learn the features of Meteor.
Go ahead and open the same url in different windows and enter your message and see the message appear on the other windows almost instantaneously. The instantaneous update is being taken care by Meteor.
I am still working on this, and plan to add some features.