I know the first image that Nest owners have in their heads is one of ads being displayed and spoken to them from their thermostats, but isn't it more likely that Google would make use of their existing mobile ad platforms and put ads in the app, and not on the actual device?

Everyone knows I'm a Google fanatic, but I'd never want them to put ads on the actual device. On the app, however, I don't see it being the end of the world.