I do not believe there is currently any support from receiving updates about a LIFX bulb that may have changed state via some other control mechanism. That is, the ability to write an application that can detect a bulb has been turned on or off via the mobile app or some other method (other than by polling).
Are there any plans to support this in the HTTP API at some point (via webhooks or some other means)? The ability to do so is crucial for building a great application that is responsive to the user.