Below is a small chat application I was able to quickly throw together using socket.io. This utilizes web sockets as well as a session token to identify users and communicate specfic data between users. This was quickly thrown together and therefore fairly basic in features, but does allow for custom usernames and custom colored messages, both configurable by the user after choosing an initial username. This does not contain user-to-user messaging and all messages are visible to any client currently connected to the server. A better example of private message can be found in this site's contact form which operates on similar principles with a vastly different implementation.