Latterati - people who frequent bookstores, but only to use the on-site coffee shops and read the free magazines.

Less than zero - a customer who costs more to serve than they return in value - i.e. someone who tries everything on and buys the cheapest thing in the shop; someone who ties up complaint / enquiry lines for hours, etc.

Little big spenders - the increasingly affluent (and interesting to advertisers) under 16s.