When I'm done reading what I want from the "New Post's" I go to the Home Page (Click on the InspectionNews logo at the top of the page, "Message Board" on the right menu or "InspectionNews" in text on the bottom right of any page). On the home page click on "Mark Forums Read" on the bottom of the listed categories right under the last one "H E L P !"

Now you have a fresh slate.