What makes them incomparable, in your view? The medium in which it's recorded? The ease with which it's recorded by Spotify? That the recording task is done in a different system than the client-server interaction? That Spotify has interactions with LOTS of people?
I get that they feel different, but every distinction I come up with feels like it either doesn't make sense applied uniformly. If I tracked songs in Excel, Spotify doesn't own that. If I automated tracking the songs I play, Spotify still doesn't own my recording. If I wrote down all my Spotify songs AND all my Skype messages AND all my texts, Spotify, Skype, and Verizon don't suddenly gain an ownership stake in what I've done.
