According to analysts, Pandora will continue to struggle with profitability until it significantly increases the number of ads it serves and improves the way those ads are targeted. Link.
How is this a benefit to the user? If Pandora was created to solve a problem - roughly because "FM radio sucked..," - why would it emulate the FM radio business model? If you follow the link above you will note that the article points out that Pandora hasn't had one full profitable year in its history. Shareholders will expect it to become profitable, therefore Pandora will have to ramp up the ads.
Same as it ever was.