In the preferences screen, nothing suggests that additional setup is needed to enable moodbar. This led me to believe that this functionality is broken. I only found out about the additional requirements when I found bug 303611 while trying to report this "bug". A note in the preference screen with a link to the relevant section in the handbook would make it easier to find. Also, it would avoid Amarok looking broken. Reproducible: Always
*** This bug has been marked as a duplicate of bug 289483 ***