Satellite radio is predicated on the idea that listeners desperate for an escape from the bland sameness of corporate radio will be willing to pay for niche broadcasting aimed directly at them. And certainly, any radio service offering options as diverse as public radio exile Bob Edwards and shock jocks Opie & Anthony must be said to be making good on its claims of wide-ranging service. Currently, the two satellite services available in the U.S. have only 3.1 million subscribers between them, but XM’s subscriber rolls have jumped 19 percent in the months since Edwards was hired away from NPR, and many observers expect the numbers to continue to increase.