The YouTube tab of the Publish window is very similar to the Movie tab. The only difference is that there are no Save as and Compression options.
To create a YouTube movie of shots or slides:
The YouTube Account Login window prompts you for your YouTube login information.
You are prompted to save the movie to your local hard disk, to the cloud, or both. This depends on what you selected in the Publish box of the Publish to YouTube window. The file will be uploaded to YouTube after you save it.
Showcase creates the movie file and uploads it to YouTube. Depending on the size of the movie and the speed of your internet connection, this may take several minutes.
A browser window opens at the YouTube page, and Showcase opens a new email message on your behalf including a link to the YouTube movie.