This is a comprehensive guide to improving AJAX performance, including a guide to a Firefox plugin I hadn’t come across before - YSlow.
To me, AJAX performance isn’t so much a scalability issue, as a user interface one. The slicker and more responsive the interface, the better the user experience. And so a deeper understanding of the AJAX protocol has got to be a good thing.
http://www.ibm.com/developerworks/web/library/wa-aj-perform/?ca=dgr-lnxw01FasterAjax






