When online retailer Bol.com saw the Dutch version of the sixth Harry Potter book coming, they immediately decided to launch a viral campaign to drive reservations for the book to their site. This way they could steal wind from the traditional bookstores.The viral campaign put a typical Potter element at the heart of the campaign – the “howler” from the movie. It was translated into a digital version called Scream Mail. Consumers can use their PC Microphone or 0800 number to record a personal message, tweak it, add magical background noises and send it on via e-mail.