BYTubeD stands for "Bulk YouTube video Downloader" (or "Batch YouTube video Downloader"). It is a Firefox extension that helps in downloading YouTube videos in bulk (i.e., downloading multiple YouTube videos at once in batch mode with a few clicks). It can be used to download all/selected YouTube videos on any page which has some YouTube video links. It makes the job of downloading YouTube playlists easy.
To install BYTubeD, please visit this page and click on "Add to Firefox".
Once BYTubeD is installed, it can be invoked by clicking on the BYTubeD menu item in the Tools menu or in the context menu. To know more about how to use BYTubeD, please see the Help page.