During the early days of the California Gold Rush, gold was easy to  find -- even with the simplest of tools. But once the easy gold was  taken, prospectors had to turn to more inventive techniques to find  the gold that remained. There are numerous similarities between gold mining and direct mail  marketing today. Rather than using a knife, pick, shovel and a pan,  we began using 4 inch by 6 inch index cards, which later developed  into more inventive mining techniques and sophisticated database  solutions. For instance, take the act of prospecting for new constituents. Are  we not panning for gold - looking for that one person in 100? And  what about after we've acquired that one person? Did we acquire gold,  or was it fool's gold? It's my belief that within every batch of new responders the ratio of  gold to fool's gold is no better than 15 percent to 85 percent.  Therefore the largest percentage