Crazy Egg is a good heat map generator, however you can also get your own heat map from here http://www.labsmedia.com/clickheat/index.php
a heat map is where ppl CLICK the most ! hence most important for adsense placement on pages and for re-organizing templates to allow ad units to be on hot spots of your pages in blog, forum and static files as well thats the reason why Google publishes all 3 heat maps since long - to assist adsense publishers to be more successful in earning $
I used the heat map yesterday for my 5,000 visitors it allows me on crazyegg. I must say I didn't learn anything from it lol. All I found out was 4000 people clicked on the same link to another part of the site that the heatmap wasn't on lol. Still a good idea though I will have to implement it better next month.
your experiment shows 2 things 1. most important - you have your site links in a hot spot to keep the visitors on your site 2. those who did NOT click on your site apparently could NOT find an adsense unite on a hotspot else you would have seen 2 areas they click one to stay on your site another hotspot area for all those who leave your site would leave to some percentage via a truly relevant adsense unite rather than just closing the window
It looks good enough, I'll give it a try. For anyone thinking of installing it, just remeber to have a deep look TWICE in to the noscript area of the standard code they give.