Google Website Optimizer
Google released a tool called Website Optimizer. If website traffic heat maps like CrazyEgg, ClickDensity or Google Analytics’ own heat map interest you, this looks like the next generation of that kind of tool.
It’s certainly not for everyone. It can be especially useful if you sell products on your site. If you are new to optimizing your site for sales, google also made a flash video containing some basics and useful advice like the use of a landing page and a call to action. They also decribe that testing is very important. For example: by testing different headlines and different images you can measure what works best on your site in terms of user actions and sales.