Spanking is inappropriate and ineffective for adolescents. With younger children, I think that there are much better discipline methods. Wouldn't you rather that your child is obedient out of love and respect for you, than because they are afraid of getting hit? Parents who spank frequently tend not to learn better ways to interact with their children and life turns into a constrant struggle where the parent stays on top by virtue of being bigger and stronger, not by earning the child's love and respect.

That said, there is a window between the ages of about 2 and 6 where a rare swat on the behind might be effective. It works because of the shock value though, so while it can be a powerful tool maybe once or twice (in the child's lifetime), more than that loses that shock value and teaches the child that mom or dad is big and mean. When it is rare, and the child gets out of control, a quick paddle gets their attention because they know they must have really done it in order to get spanked.

Just my 2 cents,
Rap