Allow users to manage their 'library'

I don't have the upload bandwidth to upload my actual music library (it would take me ... about a month, according to some quick scribbles on the back of a receipt). However, I still want to keep track of the music / artists / albums I like on Grooveshark. The "loved" feature simply isn't enough — I don't *love* all of these artists. I don't necessarily even like them. I just listen to them.

The "smart" features aren't complete enough yet, either, that they can replace the need for a library; I can't simply play one of my "truely *loved*" tracks and then expect Autoplay to find stuff I like as if it were coming out of my own library. I spend a good 20% of my time when Grooveshark is on autoplay, just "frownie-ing" shitty music.

So, what I really need, is a way to add songs, that I didn't upload to my library. And remove them thereafter. I need to construct a list of songs that I can select from / shuffle from / create playlists from.