Satellite radio is gaining traction. And as it gains credibility, it i changing the programming landscape. “Total subscribers at XM and its competitor, Sirius Satellite Radio, will probably surpass eight million by the end of year, making satellite radio one of the fastest-growing technologies ever – faster, for example, than cellphones. To keep that growth soaring, XM and Sirius are furiously signing up carmakers to offer satellite radio as a factory-installed option and are paying tens of millions of dollars for exclusive programming.”