This is just a showcase web application. Used for testing ideas for client/server interaction.
To provide support for asynchronous communication, node.js serves a WebSocket server, and two ZeroMQ (0MQ) queues. The first queue is a push-pull queue that lets anything on the server push events to the hub. The hub then publishes the events to the second, pub-sub queue. This queue lets any thread subscribe to any event type/topic.
Each WebSocket client can send in "subscribe" messages, which makes the client's server thread subscribe to the corresponding event type in the pub-sub queue. Each subscribed message from the queue is then immediately sent to the client over the WebSocket, where the client code runs a handler function for that message type.
If you're worthy, you can look up the Tech-c Handle on my domain name. May the force be with you ;-)