What can we do with this method?
We can gather some basic information about the user, like the screen resolution (when the browser is maximized) and which browser (or engine) is used. Further we can detect if a user opens a link or hovers with the mouse over an element. This can be used to track which (external) links a user visits and using the hover method. It should be even possible to track how the user moved their mouse (using an invisible table of fields in the page background). However, using my method it’s only possible to track when a user visits a link the first time or hovers over a field the first time. Maybe it’s possible to modify the method so that it is possible to track every click.
Furthermore it is possible to detect if a user has installed a specific font. Based on this information it should be possible to detect, which OS a users uses (because different operating systems ship different fonts, e.g. “Calibri” on Windows).