Spotify is not the first internet music service. There's Pandora, Rhapsody, MOG, Rdio, Zune, iTunes, Amazon Music, Google Music, and plenty of others. Yet despite not having a product in the US, Spotify became legend. A musical unicorn.
Now, finally, after years of rumor and speculation, Spotify has its greencard, with a product not unlike the one in Europe. It doesn't do anything truly unique from any of these other services, but where each of the other services approaches the market from a different angle, Spotify tries to combine all the best features into one product.