It arrived in a flurry of publicity last week – and immediately sold out. Amazon must be very pleased with the demand for its Kindle e-book reader, eventhough the reviews have been mixed. It looks set to be one of the must-have tech toys for Christmas, so people must be breathing sighs of relief at the news on the device’s Amazon pagethat it should be back in stock by December 3. Out of five possible stars, reviewers have so far only given in two-and-a-half, although there has been praise for the inbuilt Amazon store andease of downloading material via Sprint. However, Kindle doesn’t support the widely used .pdf format, and others have wondered at some of the costs involved. That means not only the $400price of the Kindle itself, but such things as $15 monthly newspaper subscriptions.