Another curious question from me. What type of information does adsense collect from a user that simply views an adsense placement?
This blog post might help you answer that question a bit more... http://pro-seo.blogspot.com/2006/07/what-information-do-adsense-ads.html
Is no problem. Adsense itself would, in my opinion, be able to collect a lot of infomation as it would be the first point of reference for google to investigate the clicks. It is also safe to assume google just dont want to collect the information and drop it - but rather compile surfing habbits and other demographics so that they can then launch more products that will become instant favourites or capitalise on some aspect not yet tried on a large scale.