From the Spotify blog:
Are you currently sharing your Spotify account with the entire family? Want to keep your 60s soul classics playlist separate from your kids’ Frozen soundtrack and save money in the process?
Well, great news! With Spotify Family you can now invite up to four family members and share one billing account whilst keeping your listening history, recommendations and playlists completely separate.
Family subscriptions were one of the main reasons my girlfriend and I used Rdio with a family account. Now, we'll be able to give Spotify a try and see if it works better for her (understandably, she doesn't care about trying every single streaming service like I do) – and plans will also be cheaper for two users (Rdio starts at $17.99 for two members, Spotify Family will be $14.99).
Spotify Family subscriptions will be available soon.