Behavior targeting -- http://googlesystem.blogspot.com/2009/03/behavioral-targeting-in-google-adsense.html
Check the Meta codes. Google uses these meta codes to display the respective ads,so check the meta codes.
i think this may of been why... i had someone go into my wp admin and they said there was a ton of bubble gum in the footer.. so many codes were put in the footer.. when u tried to edit the footer.php it would freeze. i posted this same reply sort of in my other thread.. the guy who help fix it said it was like a virus thing? and caused the ads to change.. so i had to create new ads.