RTC/Websockets
- Websockets basics: http://www.html5rocks.com/es/tutorials/websockets/basics/
- https://developer.mozilla.org/es/docs/WebSockets-840092-dup
- http://es.wikipedia.org/wiki/WebSocket
- Pusher: adding realtime bi-directional functionality via Websockets to web and Mobile apps: http://jesidea.com/pakdb/?p=2045