when vista came out, clearly one of the biggest pain points to end users was user account control (UAC). this is the feature that requires authorization to run certain applications which would require elevated privileges...most notable being installations. osx, of course, has had this feature for a while. osx requires the user to authorize elevated changes like changing account information or other system settings, as well as installations. osx differs slightly in that once you authorize in certain areas (like sys prefs) it remains 'unlocked' until you lock it again explicitly or other actions do.
another thing that vista (and actually...