The other day a stock analyst called me. His job is to watch quick service restaurant stocks and guess which ones will go up, so he can recommend them to his clients. He hadn't been at it long and was looking for some wisdom. Of course, I told him that if I had that tuned-in crystal ball, I would be a very rich man. But, never lacking in opinions, I talked to him.

He specifically wanted to know my thoughts on one large chain that was about to embark on a whole new business within the walls of its existing restaurants. Would they be successful or a...