side note: if you use 'quote and reply' instead of quick post it makes it much easier to understand what you are referring too.

First obvious check is if it works the same when using WiFi? Is this just when you are browsing using a cell signal?

If it seems the same for all sources then the next obvious step is a reboot: switch the phone off and on again.

How are you accessing the site? I know that if I just use the web link (globe) it sends parameters to google stating that I am using an N900. I have noticed that this makes some sites run in mobile mode. Do other sites show up as mobile versions or just this one site?