Going along with w0od's reply to my post, this is what I'm feeling. Stern's greatest impact has already been factored into the PPS. NOT the subscriber base.
I'm betting that most of the Howard listeners will be getting SIRIUS JUST for Howard (as w0od has eluded to). Since Stern is still on terrestrial radio, there is no need to get a subscription yet. Because he's not due to debut until January, we won't see the bulk of those subscriptions come in until Christmas time...especially since those subscribers won't even be getting their receiver until then.
I do agree with your marketing axiom. Although, I feel that this market is still pretty far from maturity. Heck, neither company is even profitable, yet. This so-called "crowning jewel" in SIRIUS's content lineup will extend the tremendous growth that SIRIUS has seen this year.
News 
Market Data 
Discover 
AI
