I'm trying to say this without sounding offensive because that is not the point of this post.
What type of person is usually going to go after the more high tech means to get music (i.e. streaming on phone/xmsirius). The answer will be people with some money (not the metro PCS folks), educated, etc. I'm an alternative rock junkie and even when we had 99x and dave, I still listened to internet radio alternative stations like Alt Nation on XM because I liked the more deeper side of music vs the strickly hit based format most fm stations play.
With oldies, most of those folks are in fact older and usually have a little money. **NOTE: WE ARE THE EXCEPTION ON THIS BOARD BECAUSE WE HAVE AN OBSESSION WITH FM RADIO** The average person could give a damn about local radio so they get the music at the best possible place.
So with hip hop, most (not all) of the listeners are black. Blacks tend NOT to go all techy when it comes to recieving music. Some of my closest black friends still do the CD thing and would not have the slightest clue how to illegally download. Again, this is most but not all. The black community depends on FM radio because they are least likely to go out and stream pandora on their phone in their car or pay 12 bucks a month for satellite radio. Further more, I understand the hip hop stations on XM suck. That's what I have been told anyway.
What about top 40? Well, you can't go wrong with top 40 but XM does. Ever listened to their HITS Radio? My top 40 friends will listen to Z100 on XM or flip over to Power and Wild. XM's HITS station gets awful reviews from my fellow top 40 fans.
So I believe that in this market, urban and top 40 are the target formats.