Correction: The iPhone has helped Pandora double its growth rate from 20,000 new users a day to almost 40,000 and it accounts for half of Pandora’s new listeners. We regret the error.

The iPhone now accounts for about half of all of Pandora’s 17 million users, Pandora founder and chief strategy officer Tim Westergren said in an opening Q&A keynote at Digital Music Forum West. Apple’s device also doubled their growth rate from 20-plus new users a day to 40. Westergren: “It’s changed our growth trajectory… It has people thinking a little differently about what internet radio is.” Full details at paidContent.org…