Something like that happens on Quora to. When you enter email adress and not password on login screen, profile image and name of the user which is registered with that email adress are appear.
Danny Sullivan really makes a nice job however this usually is not the case, imo. Generally, Google's result page does not contain so much ad. In most cases which result page contain too much ad, ads might be even more relevant than natural results.
I do not think it is relevant to separating ads from useful content. They are probably just calculating place of content which is relevant to search keywords in the screen. This would works for images and other graphical content too.
I believe that these companies are in early stages of their life which is a more chaotic era of a company. I would suggest startup-like bigger companies such as Twitter and Facebook.
Guys, I have to say that you criticize me a little harsh. But you are educative anyway, therefore I would not complain.
I actually did not use this script in any project, I sometimes write such scripts just for fun and I decided to put them on GitHub. I recently change my repo's name to weird-scripts and I put one more script (this one is a js script). You can see its new version in this url http://goo.gl/1g6k6 and I hope that you criticize this new code too.