The display ad ecosystem these days is very complicated. Displaying one ad might involve a call to a publisher ad server, an advertiser ad server, an ad exchang

The display ad ecosystem these days is very complicated. Displaying one ad might involve a call to a publisher ad server, an advertiser ad server, an ad exchange, and a third party ad network. There's no way for the ad servers to know what kinds of other things need to be called and with what parameters, so they serve scripts which load scripts that eventually load a creative. Here's a diagram of what the market looks like right now. http://mediamemo.allthingsd.com/files/2010/09/LUMA-display-ad-map.jpg http://mediamemo.allthingsd.com/files/2010/09/LUMA-display-a...