The main page of this site displays the most recently asked questions. So while it does not filter according to what you have already read, you can scroll down from the top until you find questions that you have read previously. The Categories menu on the right will show the same type of display, but only for questions pertaining to your chosen category.
Also, the top bar of the website has a link for "Unanswered". This will display questions that have not yet been responded to by a member of the forum. This could be another helpful way of staying in touch with what is happening here.
I hope this is helpful.
-Glenn