Thread:Comments:'Worst song of all time' becomes YouTube sensation/"The song itself has been... criticised for its use of Auto-Tune."

I've always wondered about this. How exactly, other than asking, do you know if an artist is using autotune? I understand that if you pitch shift to extremes it makes things sound very odd but for normal correction of off notes, can it be heard? Can anyone give me an example of a song where you can hear the signs?