I present for the use of any who may find it useful a PHP/JavaScript programme, sizetracker.php. This code allows us to record the screen and windows sizes of JavaScript-enabled user agents visiting a page. A cookie is set to prevent repeated recordings of visits to the same page.
Sufficient documentation is provided inline to get this working - other than that, you are pretty well on your own. If anyone has any real issues with this, please post a comment against this article so that my responses are available to anyone else who may have the same problem.
Thanks to Craig Francis for pointing out the security vulnerability - now fixed.
Published Wednesday, 12th December 2007.
Smiffy at LinkedIn