[duncans]

Well I'm sorry Infinum, at least their site does something when I click the tabs across the top.

OK, looks like you're doing some sort of pjaxing of the content; problem being there is none of the usual browser feedback that suggests I should wait, seeing as your site is probably under more load that normal.

Suggestion: if you're going to use pjax-style techniques, show some sort of progress indicator when the request takes longer than a few seconds... or don't use pjax-techniques when they're really not necessary.