Agreed. 

It has had an update recently and the problem remains suggesting that they either don't know about a rendering defect, or there isn't one [many renders are patched to work with incorrect HTML that worked before on previous versions of browsers ... but nobody wants that to continue forever]. Either way, Firefox is a pretty large percentage of the browser community, even on Linux and Macs (and without looking, I am sure *BSD as well ... after all, the current MacOS is based on the code base of FreeBSD 3.x ... one of their worst releases oddly enough -- the irony!).  There are no doubt ports for many UNIX variants. 

I will install latest version of Firefox 3 on my other Windows 7 mining box [my Wife has her XP laptop locked or I would just the installation there] and see if it is specific to version 4.

If the fix is simple, it would be greatly appreciated.  Otherwise, it really isn't that big of a deal for the time being.  I use Chrome quite often for bitcoin related sites which all open when I launch the browser so that I can get to things fast and that avoids me having to have to do that with my primary browser which is Firefox 4 as that would be quite annoying watching about 6 tabs load at once on startup and a bit more slowly due to add-ins. 

EDIT:  Just tried with Firefox 3 and the site shows up just fine.  I may just go back to using Firefox 3 on my machine until they get Firefox 4 straightened out (I would suspect adding HTML5 support and improving rendering performance introduced a defect that they have not yet found or fixed).