Consider the market for movie tickets. Over the past several years the number of VCR's in the home has grown. An increase in the number of VCR's in the home signals a change in preferences.
People prefer to watch home movies rather than going to the theater.
The supply of movie tickets remains unchanged because no non-price determinants of supply have changed. Consider the market for imported cars. The U. S. announces that it will begin importing cars from Korea, Taiwan, and Russia. The demand for imported cars will not change because there has been no change in any of the non-price determinants. There will be a rightward shift in supply from S to S1.