The RIAA takes all of Pandora's profits[1]. I think if they were smart they would back off and give Pandora a little breathing room to invest in marketing and tech. [1] http://www.google.com/finance?q=NYSE%3AP&fstype=ii&e...
Actually, that's not very accurate. Those performance royalties are paid to SoundExchange, a non-profit assigned to distribute the royalties to the artists. The whole reason the labels hate Pandora is because it's the only massive service paying hundreds of millions of dollars directly to the performers, without filtering it through the labels' accounting departments.
Pandora also pays the publishers for the performance right, separately from SoundExchange. This can be a fixed percentage of revenue. Societies like ASCAP, BMI, and SESAC generally administer the rights on behalf of the publishers.
Lastly, Pandora also pays Harry Fox Agency the statutory rate for the mechanical rights. HFA in turn pays the song writers.
Here's a good breakdown from an old and entertaining (view comments) TuneCore blog post: http://blog.tunecore.com/2012/03/the-additional-10-5-spotify...