Why do people think chain letters could work?
The reason people are even tempted by these schemes is that the human mind does not have an intuitive view of geometrical progressions. Suppose we presume the chain letter to have a list of five people. You are asked to send one postcard to the person on top of the list, and remail the letter to five friends. You are promised thousands of postcards from all over the world if everyone participates. Your cost: a postcard, five photocopies and envelopes, and six stamps. Not much to risk to see what comes back…
