Aholic is right, you'll only be able to stream music on Spotify from one device at a time.
However, you are able to store 'Offline Music' on up to 3 devices. This means you will be able to listen to more than one device at a time, provided the Spotify app is set to 'Offline Mode' and you don't stream any music.
THIS IS INSAINE! I pay for the service, I don't understand why I can't listen to it in my car and at the same time my wife listen to it in her car, we should have to pay for it twice. Or fight about who gets to listen to Spotify when. Will we ever be able to listen at the same time?
How come there isn't a subscripion solution for multiple access? Technically it should be possible?
And I guess a small chunk of your userbase thinks it worth the investment just to avoid having multiple location-bound accounts.
Actually no, it's not really possible when you think about it.
Option 1: Multiple premium accounts for one subscription - If the purpose is to have a family plan, this wouldn't work because you must be 13 years or older to have a Facebook account. Also, there's no way to prevent random people from pooling money together and paying for cheaper Spotify.
Option 2: One account that can listen on multiple locations at a time - This would require you to share Facebook account details with other people. What would prevent the other people from logging into Facebook itself and reading any personal information that is usually present on Facebook?