AT&T and General Motors are announcing today a plan to team up to provide AT&T 4G service in GM cars. Perhaps it's just me, but this seems like a really dumb idea.
If you're in a car, you've got your phone with you. Your phone has 4G connectivity (or better) already. What you need is a feature where you plug your phone into your car, tethering for data and preventing your phone's battery from running down. For one thing, smartphones are on a much more rapid upgrade cycle, so a built-in car modem is likely to get obsolete well before a car. For another thing, a smartphone is going to already come with various media loaded onto it that you might want to access in the car. There's no need for a separate car-specific broadband connection except as a way for telecom companies to make overall billing even more complicated.