Has anyone tried fuzzing out content further from the mouse pointer -- perhaps with semi-transparent images or new CSS/canvas capabilities -- so that users have to move the mouse near what they're reading, thus making mouse position (for testing purposes) better model gaze?
You'll get bad data. If you put a piece of content to the side in a blurred-out box for testing, people may very well go investigate it -- unblur it and they ignore it entirely.
That's actually used for security applications, as it prevents shoulder-surfing pretty readily. I don't think the average site would want to compromise the user experience that heavily though.
