I upgraded to IE9 on my home PC and discovered that the PP Forums are completely incompatible with it, even when running in all the varying compatibility modes IE9 offers. This is just a heads up as IE9 incorporates the latest CSS3 and an improved CSS2 formatting - something that most browsers will be doing (FF4 for example). A lot of sites are having to update/recode with valid CSS/xhtml in order to comply with the new browsers.