title: How does Facebook utilize MQTT, when it is topic based?
body: <p>I am learning about MQTT, and came across an <a href="http://mqtt.org/2011/08/mqtt-used-by-facebook-messenger" rel="nofollow noreferrer">article</a>, which stated that Facebook utilizes MQTT. However, I cannot understand how it is utilized, when MQTT is topic based. Does that mean the broker creates a new topic each time I create a new chat? Wouldn't that lead to an overload of topics? If I understand it correctly, the people chatting would be publishing and subscribing to the same topic.</p>