In Apple's defense: in the iPhone settings where you can turn the sending of data on and off (General > About > Diagnostics and Usage), it also gives you access to all the data it has sent, which mostly seems to be related to cellular communication.
Other data is about location services accuracy which contains the bundle ID of the application that requested the location.
Most messages contain a device ID, but it's not the devices UDID, but some other ID, so this might actually be anonymous.
I might keep this feature turned on as cellular reception and location data might be very helpful for them to improve the antenna design.
Having reviewed this and the data logged in General > About > Diagnostics and Usage I have to say that this pretty much what I expected when I allowed it to 'Send diagnostics'.
I'm a bit of a privacy nerd, but I'm happy to keep supplying this - mainly because they asked explictly for permission.
I saw a couple of LatestCrash reports there too, along with some LowMemory ones. Messages seems to record failure/success of iMessage, maybe SMS too, sending, with very little context.
Also, AFAICT it seems it goes straight back up to Apple, not to the carriers.
One thing that just occurred to me - Wouldn't NOT having a keylogger that records every thing you put into the device also give you an edge in terms of performance?
It's on all iPhones on all carriers running all versions. However, it is not the same version, and this version of CarrierIQ covers far, far less. It is not keystroke logging, not watching web activity, not watching texts.
This version also ONLY RUNS when the iPhone is in diagnostic mode. It is set to never run while the phone is operating normally.
It's on all iPhones, they all run the same software. However, it does check your carrier and will exit or upload at different times depending on what carrier is in use — for example, 3G uploads appear to only be enabled for US carriers.
Other data is about location services accuracy which contains the bundle ID of the application that requested the location.
Most messages contain a device ID, but it's not the devices UDID, but some other ID, so this might actually be anonymous.
I might keep this feature turned on as cellular reception and location data might be very helpful for them to improve the antenna design.