I stumbled across this useful feature workaround today, when I was trying to work out how to export my Spotify playlists to something more usable – such as plain text or html.
Although there’s no programmatic way to extract playlist information (that I know of), you can highlight tracks and copy and past into another application. Each track is copied on its own line, as “[Artist] – [Track Name]” and is a hyperlink to the associated track.
Incidentally, the reason behind my tinkering with this, is that I wanted a automated way of synchronising playlists between Spotify and iTunes, although I suspect the Spotify team may beat me to this with the rumored “My Music” feature.