I think this answer should be given with a Google-related example. If we consider that Google's primary focus on advertisement strategy is context-based advertising such as Adsense and Adwords, it should be something analogue to this. I would design it so it connects with existing semantic fields stored in the platform used by the user. For example, if the user is watching TV through a TiVO platform, Google would read up his suscriptions, analyze patterns of subscription, and display related ads. Also, the content of the ads would be related to the content of the TV episode, show, or movie. Let's name an example: if the user is watching a How I Met Your Mother episode and in that precise moment, the characters are mentioning something about pest control in a neighboring house, an ad would be displayed about such topic, preferably on a regional/local context as well. This ad would be displayed with a delay of aprox. 2 minutes, to avoid it being to obvious. The ads would display in a certain area of the screen and not interrupt the TV show. That would be my answer, I hope it's helpful :)