I just recovered my playlists from my account being taken over by some foreign user, and this made me very concerned about the security that Spotify has. We have heard of leaks and whatnot, and for such a popular service, just username + password is not secure enough in my opinion. I propose that Spotify allows use of the Google Authenticator app as an extra layer of protection against any attempts of account theft. I am currently using the app already for several other websites (and games), so I can be sure I don't lose my stuff.
This extra layer of security should be optional of course. Or perhaps Spotify could implement their own authenticator into the Spotify Mobile App itself.
Update: This idea has been re-posted here: https://community.spotify.com/t5/Spotify-Ideas/2-factor-authentication/idc-p/1017979
This idea has been submitted more than 1 year ago but unfortunately hasn't gained enough kudos during that time (10 kudos/year). In order to keep an overview of the active ideas in the forum, this idea will be closed for now. Note that this does not mean the idea has been declined by Spotify.
Please feel free to re-post this idea if you still feel you want this implemented. With a little change in presentation, maybe this time it will gain the necessary support from the community.