I was watching a baseball game on TV while eating my dinner this evening when I noticed that the advertising banner behind the batter kept changing.  I noticed a Budweiser ad there, but later it changed to something else.  And later something else again.  I saw at least four different banners in that spot during the time I was eating my dinner.  At first I thought it was one of those rotating signs, but it turns out that it’s really just a blue screen.  People seeing the game live just see a blank blue wall.  The network renders an advertisement in that spot in real time so that people watching the game on TV see it.

Ain’t technology wonderful?