The standard dictionary definition of the word caricature doesn't quite get it right: Caricature is a picture, description or imitation of a person or thing in which certain striking characteristics are exaggerated in order to create a comic or grotesque effect.
Well, I would say a caricature screams at the viewer. It invokes passion—either negative or positive (sometimes both, depending on the world-view of the viewer).
For art class, my son and I have been exploring the world of caricature creation. It has really opened up new concepts and forced me to let go of quite a few inhibitions. This is truly been a great experiment.