Nope, like I thought. For "Back" to work, the entire position would have to be stored in the URL, which it is not. Clicking "Back" does absolutely nothing to the board set-up :-)
(hide) If you only look at some of the discussion boards on a regular basis you can add them to your favourite boards list by going to the Board page and clicking "Add to my favourite boards". (pauloaguia) (show all tips)