I wonder if this was for the old forum design. I've never seen that, it's always been the new (well, actually there is a slightly newer version of the new design now)

I know a few years ago (couldn't have been 2011 ...) Simon asked for people to test a mobile version and "jacob1" was added to a list of people that could see it, although I didn't really like it (things like the search bar were missing, still :P). The current site is very simple and works perfectly fine on mobile phones anyway, you can tap a post to make the buttons come up. Although the textbox sometimes glitches on my phone.