You can combine Spotify playlists by copying your songs and pasting them into a new playlist on the desktop app.
A reader by the name of Peace8 asks this question: How do I put a shortcut on the desktop so I don’t have to continually type in the name of frequently visited sites? I hope you’re not saying that ...
When you delete a Spotify playlist, it'll disappear from your Library, but it'll still be available to anyone who subscribed ...