Such actions are in breach of Spotify's licensing agreement and, in the same way as when illegally downloading with Limewire, can lead to court action being taken against you - which can get VERY expensive:
http://news.bbc.co.uk...d_8108000/8108589.stm
It can automatically split the songs into separate MP3 files and automatically put all the ID3 tags and artist's info the file. Oh, and it can remove adverts too. But obviously, using it with Spotify would be naughty.