There are few places that people spend more of their time than in their car (especially daily commuters), so it only makes sense that car manufacturers would begin to open up their technology to outside development. With many Americans spending 2-3 hours in their cars per day, and much of Europe being even half of that, this is an area ripe for the picking. Some early adopters including WSJ, Rhapsody, USA Today and Glympse.
As for monetization of these applications for the developers, what better a place for mobile ad monetization than in a car. Lack of ability to skip through advertisements as well as an attentive driver/passenger makes for a great ad spot.
Couple that with the unique ability to really focus advertisements to certain demographics and locations through the application information pass back, we have an opportunity for a lot of ad dollar spend to happen.
Ford has taken the lead in this space, but likely will be followed by other Manufacturers in the very near future. This is an exciting time for the growth of the mobile application world, and this particularly could prove to be a huge player in the game.