The Impact of Cookies on Google AdSense

A while back, Google AdSense migrated from purely contextual advertising to historical advertising. I didn't notice until I visited the Economist web site, once. Since then, it feels like 50% of the web is trying to get me to subscribe!

The difference is clearly illustrated on the screen capture. On the left, page visited using Google Chrome, my regular browser on my home computer. On the right, IE 9 beta, which I rarely use.

There are a couple of problems with the historical, cookie based advertising. The main one is that I already subscribe to both The Economist and Netflix! The second is if I click on The Economist one, it bring me to an offer for Americans only!

The advertising on this blog is now hardly worth the trouble ($100 in two years). Is cookie based advertising to blame?