Here is a list of a subset of the many deployments of MQTT (please add links to reference information and articles where possible)

• Facebook Messenger - 680M users as of Spring 2013, expected to hit 1B by 2014.

• Conoco Phillips Pipeline - 30,000 devices on 17,000 km of pipeline monitored & controlled via MQTT on satellite links. Enables real-time conditional maintenance.

• St Jude Medical - 100,000 heart pacemakers monitored via MQTT.

• Toshiba Consert - smart energy grid solution provider built on MQTT.

• Sprint Velocity - Connected Car / Telematics provider. Public about their use of IBM MessageSight hardware accelerated MQTT for "key fob" response time for smartphone->Sprint Velocity cloud->car and back.