Hi There! Do you guys know what all those "System Services under Location Services" mean? Like Compass Calibration Location Based iAds Mobile Network Search Motion calibration and distance (isn't this compass calibration ?) Wi-Fi networking - especially this! Are any of these above mandatory or very helpful or I can just turn them off since I have no clue what they are doing except sucking my battery. And also, I have the "show status bar icon" turned off not to show the icon on the top corner of the screen when locations are being used but it somehow always manages to show the little arrow. Any ideas?