I updated my iPod touch to iOS4, and connected it to my Mac. I opened Xcode's Organizer, and clicked 'Use for development.' Since then, when I open te Settings App on my iPod, there is an extra section between 'Safari' and 'Nike+' called 'Developer' (it is not Safari's debugging console!).
When I select it, the awesome navigation controller pushes me to a view where I can enable 'Logging.'
Can anyone explain me what this exactly is? My device is NOT Jailbroken.
You can enable a Debug Console in Safari on iPhone or iPod touch, which allows you to see HTML, CSS, and JavaScript errors directly on the iPhone or iPod touch. More info available here
This allows you to log the power consumption of your apps while you use the phone out and about and then view the results in Instruments.
More details here (Energy Diagnostics): http://developer.apple.com/mac/library/documentation/DeveloperTools/Conceptual/InstrumentsUserGuide/Built-InInstruments/Built-InInstruments.html
This is useful since the power usage of your app can vary greatly in the real world vs when it is directly connected to Instruments via USB.