I cannot see the logical connection here? The chromecast lets you watch youtube, netflix and listen to google music. (and to some extend to stream from chrome.) How does this change the game? As I can see it, it can only make things worse. When I stream something on my tv I'm usually not up for clicking with the mouse on some add to buy some random stuff, i do this on the PC, there isn't the habbit of doing it.
As theserp said, dafuq you on about boy? Make ads more attractive? I think you mean add an additional point of advertisement.