actually every, or most, site dev's have their own version of the website to add new features and test them, you stumbled upon the one from yoyo, you can try out other dev names to see if they have their own version.
like ~hampa and ~fish work aswell.
usually logging in worked (atleast it did for me back in the day when i knew a site dev) but maybe they deactivated it cause people were fooling around on these boards.