September listener hours likely will be down, but active listeners will probably not be affected too much yet due to the shady methods Pandora uses to count and active listener. Essentially, if a user only listens to part of one song in the prior 30 day period, they are counted as an "active" listener. They also admit in the SEC filings that active listeners may include people with multiple accounts, which skews the number higher. Of course, once October metrics come out, there will be a marked decline across the board. If Pandora only counted unique users, I'd venture to guess their "active" listener count would be closer to 50 million. Of course, if those users with multiple accounts decide to leave for iTunes Radio, it will multiply the drop in active users. Pandora's shady metrics reporting will come back to haunt them at some point.