WHEN I was a child (way back when) we collected pieces of writing paper, which we kept in photograph albums, and swopped with each other. We loved the pages that had little pictures in the corner. The pages with watermarks were especially rare and the most prized were the cheesy ones with a girl and guy holding hands running into the sunset. In the ensuing years children of all generations have had their thing for collecting. Stamps, football cards, marbles, pencils and flags — some of these childhood crazes are egged on by marketing companies that feed the urge.