Their implementation of the channel is interesting compared to say, socket.io. Its essentially a one-way-only pipe where data can flow out of the server, to a client. The server only sees it as a pipe, and never gets any data back through it, not even connects or disconnects.

Any server-bound data must be sent through a REST interface, and the corresponding state retrieved through memcache or a DB request. To track connections, the client must periodically send notifications to the server to keep it alive: "If the application needs to keep track of which clients are connected, one solution is to set the socket’s onopen property to call a function designed to send a POST message to the server at some regular interval in order to notify the server of the client's state."