Yep, I absolutely *HATE* that with a passion when I encounter it! Especially when I trawl a site for a good half hour or more, eventually find the page I want, fail to notice that the URL hasn't changed, smugly hit CTRL+D - then when I visit the bookmark later - hey presto! ... The homepage of the site.
(much purple-faced swearing, flying coffee cups, etc ...)
I have a rule for my AJAX - use it to modify existing