Shirley Mullin, owner of two Kids Ink stores in Indianapolis, is so familiar with her customers' likes and dislikes that when she sees a book she thinks they'll like, she marks their name in the publisher's catalogue. Then the person typing up the purchase order writes in the name, so the staff can alert the customer when the book comes in. "There's a guy who collects books on honey bees and a woman who collects every book ever published on horses. We have three people who collect Cinderella stories," Mullin noted. "We call them when the books come in, and they just rush right in here. It's a no-brainer."

To jog her memory about customer favorites, Mullin often writes down their interests on a note card or types them into the computer system. "It certainly doesn't count for a high percentage of our sales," said Mullin, "but they're loyal customers."