Is there a way to tag songs in the same way you would tag photos on Flickr or Facebook?  I want to listen to playlists from these tags.

For example: I'm listening to song X.  Song X is a popular, chill song that I think my girlfriend would like.  I tag it with "popular", "chill", and "girlfriend."  Then I look at a list of all my tags (could be in a tag cloud, list, or both); when I click on a tag it loads a playlist with all the songs that have that tag.

Does anyone know of a way to do this in Amarok?  Or any other music player that has this functionality?