Friend of mine just started working for BurstMedia. Can't remember if its js or a pixel but they sell real time bidding on ads. So you load a page from say CNN, as the page is loading Burst opens bidding for an ad on that page. Ad agencies place bids and whoever is highest gets the placement. All happens in a few milliseconds. Its really amazing tech.
Yea, and God said to Abraham "You will kill your son Isaac." and Abraham said, "I can't hear you, you will have to speak into the microphone." And God said, "Ohh, I'm sorry, is this better? Check, check, check, check. Jerry, pull the high end out, I'm still getting some hiss back here."