They are just using php to parse the all links on the google page. If you go to the first link on the demo where the banner is "sticky" you can see by rolling over all the links on page (when you think you're on google) and see its going thruogh the php script.
I could write that script a day. It makes people think they are hijacking spots on remote sites when its really just acting like a web browser. Just view source and you'll see what I mean.