ESPN is making a stance against the ad networks and turning them off of its properties. This is a losing effort on their part as you cannot fight the technology, you must adapt to it and make it work for you:

So can ESPN change the model? “It won’t have the desired impact,” said Adam Kasper, senior vp, director of digital media, Media Contacts, unless the top 10 or so Web sites followed suit. ESPN is “essentially fighting technology. That’s a hard thing to do.”

ESPN Turns Off Ad Nets