I thought the other night it'd be fun to see if you could just track everyone that comes to your site and see how they browse the site and move their mouse. I know there are products out there that do this already, but thought it'd be interesting to make a clone. By knowing how a user moves around your site, you might be able to get some interesting statistics about your sites usability.
As you move across this site we are recording your mouse's position. After you leave the site it sends the server all your mouse movements, and the time they were made. Different browsers handle the "window.unload" call differently. Again this is merely a demo.
You can read more about this and get the full source code over at our blog.
You can click across to the replay page to see how the system tracked your mouse, however you may need to refresh the page once or twice until your replay session is available.