ClickHeat is an open source heatmap statistics application & PHP class that visualizes your visitors clicking activities which is a very nice way of getting a snapshot of your visitor’s browsing behaviors.

Heatmaps can also be generated using its heatmap class inside other web applications.

Free Heat Map

ClickHeat is lightweight as very few function calls to log a click, no server load rise should be noticed. For tweakenings with the settings check the performance & optimization page.