Crazy Egg is great at tracking clicks on ads like AdSense. You can track where on the ad they click, test ads in different positions and of different designs (run one test for a few days, then make a change and run another one)."

Crazy Egg is like X-Ray vision for your site! By using it, we were quickly able to see where people are clicking on our landing pages. The reports Crazy Egg generated allowed us to make the changes accordingly, which helped us drastically increase the click-through rate.

There is nothing in Google Analytics that can replace the functionality Crazy Egg provides -- Google Analytics have the site overlay report, this tells you what percentage of people clicked through to what page -- but it can't tell you which part they clicked. Crazy Egg shows you where everyone has clicked, whether it was on a link or not -- this highlights usability errors and often areas that could result in an improvement in conversions.