youtube video posting

Hi - can anyone tell me why the button that used to appear on top right of every video on youtube saying "download video" does not appear anymore? Has it been stopped? I was building up quite a nice list of videos that certainly won't be around anymore - from music festivals in the 50's for example - but now it has all stopped. Does anyone know why?? Is there any toolbar I can add to make the button re-appear?? Thanks - Cate