This is pretty smart, especially with location-specific apps like HotelTonight. I'm assuming an ad-serving app could pass along my location and then display an

This is pretty smart, especially with location-specific apps like HotelTonight. I'm assuming an ad-serving app could pass along my location and then display an ad for a hotel room in that city. It's stuff like this that Groupon should be doing/looking at if they want to become relevant again.