This is the basic introductory talk on MQTT. MQTT is a pub/sub protocol for interprocess communication. One process publishes information to a topic, other processes can subscribe to that topic. There is a tree of topics, so it is ideal for managing complexity. It also supports multiple Quality Of Service Levels: fire and forget, at least once, or exactly once. MQTT is an industry standard, which runs on every platform imagine-able.
By the end of this talk you should know enough to decide if MQTT is right for your projects.